(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
(function (global){
global.PouchDB = require('pouchdb-browser');
PouchDB.plugin(require('pouchdb-adapter-memory'));
PouchDB.plugin(require('pouchdb-adapter-localstorage'));

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"pouchdb-adapter-localstorage":58,"pouchdb-adapter-memory":59,"pouchdb-browser":62}],2:[function(require,module,exports){
(function (process){
/* Copyright (c) 2013 Rod Vagg, MIT License */

function AbstractChainedBatch (db) {
  this._db         = db
  this._operations = []
  this._written    = false
}

AbstractChainedBatch.prototype._checkWritten = function () {
  if (this._written)
    throw new Error('write() already called on this batch')
}

AbstractChainedBatch.prototype.put = function (key, value) {
  this._checkWritten()

  var err = this._db._checkKeyValue(key, 'key', this._db._isBuffer)
  if (err) throw err
  err = this._db._checkKeyValue(value, 'value', this._db._isBuffer)
  if (err) throw err

  if (!this._db._isBuffer(key)) key = String(key)
  if (!this._db._isBuffer(value)) value = String(value)

  if (typeof this._put == 'function' )
    this._put(key, value)
  else
    this._operations.push({ type: 'put', key: key, value: value })

  return this
}

AbstractChainedBatch.prototype.del = function (key) {
  this._checkWritten()

  var err = this._db._checkKeyValue(key, 'key', this._db._isBuffer)
  if (err) throw err

  if (!this._db._isBuffer(key)) key = String(key)

  if (typeof this._del == 'function' )
    this._del(key)
  else
    this._operations.push({ type: 'del', key: key })

  return this
}

AbstractChainedBatch.prototype.clear = function () {
  this._checkWritten()

  this._operations = []

  if (typeof this._clear == 'function' )
    this._clear()

  return this
}

AbstractChainedBatch.prototype.write = function (options, callback) {
  this._checkWritten()

  if (typeof options == 'function')
    callback = options
  if (typeof callback != 'function')
    throw new Error('write() requires a callback argument')
  if (typeof options != 'object')
    options = {}

  this._written = true

  if (typeof this._write == 'function' )
    return this._write(callback)

  if (typeof this._db._batch == 'function')
    return this._db._batch(this._operations, options, callback)

  process.nextTick(callback)
}

module.exports = AbstractChainedBatch
}).call(this,require('_process'))
},{"_process":113}],3:[function(require,module,exports){
(function (process){
/* Copyright (c) 2013 Rod Vagg, MIT License */

function AbstractIterator (db) {
  this.db = db
  this._ended = false
  this._nexting = false
}

AbstractIterator.prototype.next = function (callback) {
  var self = this

  if (typeof callback != 'function')
    throw new Error('next() requires a callback argument')

  if (self._ended)
    return callback(new Error('cannot call next() after end()'))
  if (self._nexting)
    return callback(new Error('cannot call next() before previous next() has completed'))

  self._nexting = true
  if (typeof self._next == 'function') {
    return self._next(function () {
      self._nexting = false
      callback.apply(null, arguments)
    })
  }

  process.nextTick(function () {
    self._nexting = false
    callback()
  })
}

AbstractIterator.prototype.end = function (callback) {
  if (typeof callback != 'function')
    throw new Error('end() requires a callback argument')

  if (this._ended)
    return callback(new Error('end() already called on iterator'))

  this._ended = true

  if (typeof this._end == 'function')
    return this._end(callback)

  process.nextTick(callback)
}

module.exports = AbstractIterator

}).call(this,require('_process'))
},{"_process":113}],4:[function(require,module,exports){
(function (Buffer,process){
/* Copyright (c) 2013 Rod Vagg, MIT License */

var xtend                = require('xtend')
  , AbstractIterator     = require('./abstract-iterator')
  , AbstractChainedBatch = require('./abstract-chained-batch')

function AbstractLevelDOWN (location) {
  if (!arguments.length || location === undefined)
    throw new Error('constructor requires at least a location argument')

  if (typeof location != 'string')
    throw new Error('constructor requires a location string argument')

  this.location = location
}

AbstractLevelDOWN.prototype.open = function (options, callback) {
  if (typeof options == 'function')
    callback = options

  if (typeof callback != 'function')
    throw new Error('open() requires a callback argument')

  if (typeof options != 'object')
    options = {}

  if (typeof this._open == 'function')
    return this._open(options, callback)

  process.nextTick(callback)
}

AbstractLevelDOWN.prototype.close = function (callback) {
  if (typeof callback != 'function')
    throw new Error('close() requires a callback argument')

  if (typeof this._close == 'function')
    return this._close(callback)

  process.nextTick(callback)
}

AbstractLevelDOWN.prototype.get = function (key, options, callback) {
  var err

  if (typeof options == 'function')
    callback = options

  if (typeof callback != 'function')
    throw new Error('get() requires a callback argument')

  if (err = this._checkKeyValue(key, 'key', this._isBuffer))
    return callback(err)

  if (!this._isBuffer(key))
    key = String(key)

  if (typeof options != 'object')
    options = {}

  if (typeof this._get == 'function')
    return this._get(key, options, callback)

  process.nextTick(function () { callback(new Error('NotFound')) })
}

AbstractLevelDOWN.prototype.put = function (key, value, options, callback) {
  var err

  if (typeof options == 'function')
    callback = options

  if (typeof callback != 'function')
    throw new Error('put() requires a callback argument')

  if (err = this._checkKeyValue(key, 'key', this._isBuffer))
    return callback(err)

  if (err = this._checkKeyValue(value, 'value', this._isBuffer))
    return callback(err)

  if (!this._isBuffer(key))
    key = String(key)

  // coerce value to string in node, don't touch it in browser
  // (indexeddb can store any JS type)
  if (!this._isBuffer(value) && !process.browser)
    value = String(value)

  if (typeof options != 'object')
    options = {}

  if (typeof this._put == 'function')
    return this._put(key, value, options, callback)

  process.nextTick(callback)
}

AbstractLevelDOWN.prototype.del = function (key, options, callback) {
  var err

  if (typeof options == 'function')
    callback = options

  if (typeof callback != 'function')
    throw new Error('del() requires a callback argument')

  if (err = this._checkKeyValue(key, 'key', this._isBuffer))
    return callback(err)

  if (!this._isBuffer(key))
    key = String(key)

  if (typeof options != 'object')
    options = {}

  if (typeof this._del == 'function')
    return this._del(key, options, callback)

  process.nextTick(callback)
}

AbstractLevelDOWN.prototype.batch = function (array, options, callback) {
  if (!arguments.length)
    return this._chainedBatch()

  if (typeof options == 'function')
    callback = options

  if (typeof callback != 'function')
    throw new Error('batch(array) requires a callback argument')

  if (!Array.isArray(array))
    return callback(new Error('batch(array) requires an array argument'))

  if (typeof options != 'object')
    options = {}

  var i = 0
    , l = array.length
    , e
    , err

  for (; i < l; i++) {
    e = array[i]
    if (typeof e != 'object')
      continue

    if (err = this._checkKeyValue(e.type, 'type', this._isBuffer))
      return callback(err)

    if (err = this._checkKeyValue(e.key, 'key', this._isBuffer))
      return callback(err)

    if (e.type == 'put') {
      if (err = this._checkKeyValue(e.value, 'value', this._isBuffer))
        return callback(err)
    }
  }

  if (typeof this._batch == 'function')
    return this._batch(array, options, callback)

  process.nextTick(callback)
}

//TODO: remove from here, not a necessary primitive
AbstractLevelDOWN.prototype.approximateSize = function (start, end, callback) {
  if (   start == null
      || end == null
      || typeof start == 'function'
      || typeof end == 'function') {
    throw new Error('approximateSize() requires valid `start`, `end` and `callback` arguments')
  }

  if (typeof callback != 'function')
    throw new Error('approximateSize() requires a callback argument')

  if (!this._isBuffer(start))
    start = String(start)

  if (!this._isBuffer(end))
    end = String(end)

  if (typeof this._approximateSize == 'function')
    return this._approximateSize(start, end, callback)

  process.nextTick(function () {
    callback(null, 0)
  })
}

AbstractLevelDOWN.prototype._setupIteratorOptions = function (options) {
  var self = this

  options = xtend(options)

  ;[ 'start', 'end', 'gt', 'gte', 'lt', 'lte' ].forEach(function (o) {
    if (options[o] && self._isBuffer(options[o]) && options[o].length === 0)
      delete options[o]
  })

  options.reverse = !!options.reverse

  // fix `start` so it takes into account gt, gte, lt, lte as appropriate
  if (options.reverse && options.lt)
    options.start = options.lt
  if (options.reverse && options.lte)
    options.start = options.lte
  if (!options.reverse && options.gt)
    options.start = options.gt
  if (!options.reverse && options.gte)
    options.start = options.gte

  if ((options.reverse && options.lt && !options.lte)
    || (!options.reverse && options.gt && !options.gte))
    options.exclusiveStart = true // start should *not* include matching key

  return options
}

AbstractLevelDOWN.prototype.iterator = function (options) {
  if (typeof options != 'object')
    options = {}

  options = this._setupIteratorOptions(options)

  if (typeof this._iterator == 'function')
    return this._iterator(options)

  return new AbstractIterator(this)
}

AbstractLevelDOWN.prototype._chainedBatch = function () {
  return new AbstractChainedBatch(this)
}

AbstractLevelDOWN.prototype._isBuffer = function (obj) {
  return Buffer.isBuffer(obj)
}

AbstractLevelDOWN.prototype._checkKeyValue = function (obj, type) {
  if (obj === null || obj === undefined)
    return new Error(type + ' cannot be `null` or `undefined`')

  if (obj === null || obj === undefined)
    return new Error(type + ' cannot be `null` or `undefined`')

  if (this._isBuffer(obj)) {
    if (obj.length === 0)
      return new Error(type + ' cannot be an empty Buffer')
  } else if (String(obj) === '')
    return new Error(type + ' cannot be an empty String')
}

module.exports.AbstractLevelDOWN    = AbstractLevelDOWN
module.exports.AbstractIterator     = AbstractIterator
module.exports.AbstractChainedBatch = AbstractChainedBatch

}).call(this,{"isBuffer":require("../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js")},require('_process'))
},{"../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js":110,"./abstract-chained-batch":2,"./abstract-iterator":3,"_process":113,"xtend":101}],5:[function(require,module,exports){
'use strict';

module.exports = argsArray;

function argsArray(fun) {
  return function () {
    var len = arguments.length;
    if (len) {
      var args = [];
      var i = -1;
      while (++i < len) {
        args[i] = arguments[i];
      }
      return fun.call(this, args);
    } else {
      return fun.call(this, []);
    }
  };
}
},{}],6:[function(require,module,exports){
(function (Buffer){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.

function isArray(arg) {
  if (Array.isArray) {
    return Array.isArray(arg);
  }
  return objectToString(arg) === '[object Array]';
}
exports.isArray = isArray;

function isBoolean(arg) {
  return typeof arg === 'boolean';
}
exports.isBoolean = isBoolean;

function isNull(arg) {
  return arg === null;
}
exports.isNull = isNull;

function isNullOrUndefined(arg) {
  return arg == null;
}
exports.isNullOrUndefined = isNullOrUndefined;

function isNumber(arg) {
  return typeof arg === 'number';
}
exports.isNumber = isNumber;

function isString(arg) {
  return typeof arg === 'string';
}
exports.isString = isString;

function isSymbol(arg) {
  return typeof arg === 'symbol';
}
exports.isSymbol = isSymbol;

function isUndefined(arg) {
  return arg === void 0;
}
exports.isUndefined = isUndefined;

function isRegExp(re) {
  return objectToString(re) === '[object RegExp]';
}
exports.isRegExp = isRegExp;

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}
exports.isObject = isObject;

function isDate(d) {
  return objectToString(d) === '[object Date]';
}
exports.isDate = isDate;

function isError(e) {
  return (objectToString(e) === '[object Error]' || e instanceof Error);
}
exports.isError = isError;

function isFunction(arg) {
  return typeof arg === 'function';
}
exports.isFunction = isFunction;

function isPrimitive(arg) {
  return arg === null ||
         typeof arg === 'boolean' ||
         typeof arg === 'number' ||
         typeof arg === 'string' ||
         typeof arg === 'symbol' ||  // ES6 symbol
         typeof arg === 'undefined';
}
exports.isPrimitive = isPrimitive;

exports.isBuffer = Buffer.isBuffer;

function objectToString(o) {
  return Object.prototype.toString.call(o);
}

}).call(this,{"isBuffer":require("../../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js")})
},{"../../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js":110}],7:[function(require,module,exports){
var Buffer = require('buffer').Buffer

var CHARS = '.PYFGCRLAOEUIDHTNSQJKXBMWVZ_pyfgcrlaoeuidhtnsqjkxbmwvz1234567890'
  .split('').sort().join('')

module.exports = function (chars, exports) {
  chars = chars || CHARS
  exports = exports || {}
  if(chars.length !== 64) throw new Error('a base 64 encoding requires 64 chars')

  var codeToIndex = new Buffer(128)
  codeToIndex.fill()

  for(var i = 0; i < 64; i++) {
    var code = chars.charCodeAt(i)
    codeToIndex[code] = i
  }

  exports.encode = function (data) {
      var s = '', l = data.length, hang = 0
      for(var i = 0; i < l; i++) {
        var v = data[i]

        switch (i % 3) {
          case 0:
            s += chars[v >> 2]
            hang = (v & 3) << 4
          break;
          case 1:
            s += chars[hang | v >> 4]
            hang = (v & 0xf) << 2
          break;
          case 2:
            s += chars[hang | v >> 6]
            s += chars[v & 0x3f]
            hang = 0
          break;
        }

      }
      if(l%3) s += chars[hang]
      return s
    }
  exports.decode = function (str) {
      var l = str.length, j = 0
      var b = new Buffer(~~((l/4)*3)), hang = 0

      for(var i = 0; i < l; i++) {
        var v = codeToIndex[str.charCodeAt(i)]

        switch (i % 4) {
          case 0:
            hang = v << 2;
          break;
          case 1:
            b[j++] = hang | v >> 4
            hang = (v << 4) & 0xff
          break;
          case 2:
            b[j++] = hang | v >> 2
            hang = (v << 6) & 0xff
          break;
          case 3:
            b[j++] = hang | v
          break;
        }

      }
      return b
    }
  return exports
}

module.exports(CHARS, module.exports)


},{"buffer":105}],8:[function(require,module,exports){

/**
 * This is the web browser implementation of `debug()`.
 *
 * Expose `debug()` as the module.
 */

exports = module.exports = require('./debug');
exports.log = log;
exports.formatArgs = formatArgs;
exports.save = save;
exports.load = load;
exports.useColors = useColors;
exports.storage = 'undefined' != typeof chrome
               && 'undefined' != typeof chrome.storage
                  ? chrome.storage.local
                  : localstorage();

/**
 * Colors.
 */

exports.colors = [
  'lightseagreen',
  'forestgreen',
  'goldenrod',
  'dodgerblue',
  'darkorchid',
  'crimson'
];

/**
 * Currently only WebKit-based Web Inspectors, Firefox >= v31,
 * and the Firebug extension (any Firefox version) are known
 * to support "%c" CSS customizations.
 *
 * TODO: add a `localStorage` variable to explicitly enable/disable colors
 */

function useColors() {
  // is webkit? http://stackoverflow.com/a/16459606/376773
  return ('WebkitAppearance' in document.documentElement.style) ||
    // is firebug? http://stackoverflow.com/a/398120/376773
    (window.console && (console.firebug || (console.exception && console.table))) ||
    // is firefox >= v31?
    // https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
    (navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/) && parseInt(RegExp.$1, 10) >= 31);
}

/**
 * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
 */

exports.formatters.j = function(v) {
  return JSON.stringify(v);
};


/**
 * Colorize log arguments if enabled.
 *
 * @api public
 */

function formatArgs() {
  var args = arguments;
  var useColors = this.useColors;

  args[0] = (useColors ? '%c' : '')
    + this.namespace
    + (useColors ? ' %c' : ' ')
    + args[0]
    + (useColors ? '%c ' : ' ')
    + '+' + exports.humanize(this.diff);

  if (!useColors) return args;

  var c = 'color: ' + this.color;
  args = [args[0], c, 'color: inherit'].concat(Array.prototype.slice.call(args, 1));

  // the final "%c" is somewhat tricky, because there could be other
  // arguments passed either before or after the %c, so we need to
  // figure out the correct index to insert the CSS into
  var index = 0;
  var lastC = 0;
  args[0].replace(/%[a-z%]/g, function(match) {
    if ('%%' === match) return;
    index++;
    if ('%c' === match) {
      // we only are interested in the *last* %c
      // (the user may have provided their own)
      lastC = index;
    }
  });

  args.splice(lastC, 0, c);
  return args;
}

/**
 * Invokes `console.log()` when available.
 * No-op when `console.log` is not a "function".
 *
 * @api public
 */

function log() {
  // this hackery is required for IE8/9, where
  // the `console.log` function doesn't have 'apply'
  return 'object' === typeof console
    && console.log
    && Function.prototype.apply.call(console.log, console, arguments);
}

/**
 * Save `namespaces`.
 *
 * @param {String} namespaces
 * @api private
 */

function save(namespaces) {
  try {
    if (null == namespaces) {
      exports.storage.removeItem('debug');
    } else {
      exports.storage.debug = namespaces;
    }
  } catch(e) {}
}

/**
 * Load `namespaces`.
 *
 * @return {String} returns the previously persisted debug modes
 * @api private
 */

function load() {
  var r;
  try {
    r = exports.storage.debug;
  } catch(e) {}
  return r;
}

/**
 * Enable namespaces listed in `localStorage.debug` initially.
 */

exports.enable(load());

/**
 * Localstorage attempts to return the localstorage.
 *
 * This is necessary because safari throws
 * when a user disables cookies/localstorage
 * and you attempt to access it.
 *
 * @return {LocalStorage}
 * @api private
 */

function localstorage(){
  try {
    return window.localStorage;
  } catch (e) {}
}

},{"./debug":9}],9:[function(require,module,exports){

/**
 * This is the common logic for both the Node.js and web browser
 * implementations of `debug()`.
 *
 * Expose `debug()` as the module.
 */

exports = module.exports = debug;
exports.coerce = coerce;
exports.disable = disable;
exports.enable = enable;
exports.enabled = enabled;
exports.humanize = require('ms');

/**
 * The currently active debug mode names, and names to skip.
 */

exports.names = [];
exports.skips = [];

/**
 * Map of special "%n" handling functions, for the debug "format" argument.
 *
 * Valid key names are a single, lowercased letter, i.e. "n".
 */

exports.formatters = {};

/**
 * Previously assigned color.
 */

var prevColor = 0;

/**
 * Previous log timestamp.
 */

var prevTime;

/**
 * Select a color.
 *
 * @return {Number}
 * @api private
 */

function selectColor() {
  return exports.colors[prevColor++ % exports.colors.length];
}

/**
 * Create a debugger with the given `namespace`.
 *
 * @param {String} namespace
 * @return {Function}
 * @api public
 */

function debug(namespace) {

  // define the `disabled` version
  function disabled() {
  }
  disabled.enabled = false;

  // define the `enabled` version
  function enabled() {

    var self = enabled;

    // set `diff` timestamp
    var curr = +new Date();
    var ms = curr - (prevTime || curr);
    self.diff = ms;
    self.prev = prevTime;
    self.curr = curr;
    prevTime = curr;

    // add the `color` if not set
    if (null == self.useColors) self.useColors = exports.useColors();
    if (null == self.color && self.useColors) self.color = selectColor();

    var args = Array.prototype.slice.call(arguments);

    args[0] = exports.coerce(args[0]);

    if ('string' !== typeof args[0]) {
      // anything else let's inspect with %o
      args = ['%o'].concat(args);
    }

    // apply any `formatters` transformations
    var index = 0;
    args[0] = args[0].replace(/%([a-z%])/g, function(match, format) {
      // if we encounter an escaped % then don't increase the array index
      if (match === '%%') return match;
      index++;
      var formatter = exports.formatters[format];
      if ('function' === typeof formatter) {
        var val = args[index];
        match = formatter.call(self, val);

        // now we need to remove `args[index]` since it's inlined in the `format`
        args.splice(index, 1);
        index--;
      }
      return match;
    });

    if ('function' === typeof exports.formatArgs) {
      args = exports.formatArgs.apply(self, args);
    }
    var logFn = enabled.log || exports.log || console.log.bind(console);
    logFn.apply(self, args);
  }
  enabled.enabled = true;

  var fn = exports.enabled(namespace) ? enabled : disabled;

  fn.namespace = namespace;

  return fn;
}

/**
 * Enables a debug mode by namespaces. This can include modes
 * separated by a colon and wildcards.
 *
 * @param {String} namespaces
 * @api public
 */

function enable(namespaces) {
  exports.save(namespaces);

  var split = (namespaces || '').split(/[\s,]+/);
  var len = split.length;

  for (var i = 0; i < len; i++) {
    if (!split[i]) continue; // ignore empty strings
    namespaces = split[i].replace(/\*/g, '.*?');
    if (namespaces[0] === '-') {
      exports.skips.push(new RegExp('^' + namespaces.substr(1) + '$'));
    } else {
      exports.names.push(new RegExp('^' + namespaces + '$'));
    }
  }
}

/**
 * Disable debug output.
 *
 * @api public
 */

function disable() {
  exports.enable('');
}

/**
 * Returns true if the given mode name is enabled, false otherwise.
 *
 * @param {String} name
 * @return {Boolean}
 * @api public
 */

function enabled(name) {
  var i, len;
  for (i = 0, len = exports.skips.length; i < len; i++) {
    if (exports.skips[i].test(name)) {
      return false;
    }
  }
  for (i = 0, len = exports.names.length; i < len; i++) {
    if (exports.names[i].test(name)) {
      return true;
    }
  }
  return false;
}

/**
 * Coerce `val`.
 *
 * @param {Mixed} val
 * @return {Mixed}
 * @api private
 */

function coerce(val) {
  if (val instanceof Error) return val.stack || val.message;
  return val;
}

},{"ms":56}],10:[function(require,module,exports){
var util = require('util')
  , AbstractIterator = require('abstract-leveldown').AbstractIterator


function DeferredIterator (options) {
  AbstractIterator.call(this, options)

  this._options = options
  this._iterator = null
  this._operations = []
}

util.inherits(DeferredIterator, AbstractIterator)

DeferredIterator.prototype.setDb = function (db) {
  var it = this._iterator = db.iterator(this._options)
  this._operations.forEach(function (op) {
    it[op.method].apply(it, op.args)
  })
}

DeferredIterator.prototype._operation = function (method, args) {
  if (this._iterator)
    return this._iterator[method].apply(this._iterator, args)
  this._operations.push({ method: method, args: args })
}

'next end'.split(' ').forEach(function (m) {
  DeferredIterator.prototype['_' + m] = function () {
    this._operation(m, arguments)
  }
})

module.exports = DeferredIterator;

},{"abstract-leveldown":15,"util":129}],11:[function(require,module,exports){
(function (Buffer,process){
var util              = require('util')
  , AbstractLevelDOWN = require('abstract-leveldown').AbstractLevelDOWN
  , DeferredIterator  = require('./deferred-iterator')

function DeferredLevelDOWN (location) {
  AbstractLevelDOWN.call(this, typeof location == 'string' ? location : '') // optional location, who cares?
  this._db         = undefined
  this._operations = []
  this._iterators  = []
}

util.inherits(DeferredLevelDOWN, AbstractLevelDOWN)

// called by LevelUP when we have a real DB to take its place
DeferredLevelDOWN.prototype.setDb = function (db) {
  this._db = db
  this._operations.forEach(function (op) {
    db[op.method].apply(db, op.args)
  })
  this._iterators.forEach(function (it) {
    it.setDb(db)
  })
}

DeferredLevelDOWN.prototype._open = function (options, callback) {
  return process.nextTick(callback)
}

// queue a new deferred operation
DeferredLevelDOWN.prototype._operation = function (method, args) {
  if (this._db)
    return this._db[method].apply(this._db, args)
  this._operations.push({ method: method, args: args })
}

// deferrables
'put get del batch approximateSize'.split(' ').forEach(function (m) {
  DeferredLevelDOWN.prototype['_' + m] = function () {
    this._operation(m, arguments)
  }
})

DeferredLevelDOWN.prototype._isBuffer = function (obj) {
  return Buffer.isBuffer(obj)
}

DeferredLevelDOWN.prototype._iterator = function (options) {
  if (this._db)
    return this._db.iterator.apply(this._db, arguments)
  var it = new DeferredIterator(options)
  this._iterators.push(it)
  return it
}

module.exports                  = DeferredLevelDOWN
module.exports.DeferredIterator = DeferredIterator

}).call(this,{"isBuffer":require("../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js")},require('_process'))
},{"../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js":110,"./deferred-iterator":10,"_process":113,"abstract-leveldown":15,"util":129}],12:[function(require,module,exports){
(function (process){
/* Copyright (c) 2013 Rod Vagg, MIT License */

function AbstractChainedBatch (db) {
  this._db         = db
  this._operations = []
  this._written    = false
}

AbstractChainedBatch.prototype._checkWritten = function () {
  if (this._written)
    throw new Error('write() already called on this batch')
}

AbstractChainedBatch.prototype.put = function (key, value) {
  this._checkWritten()

  var err = this._db._checkKey(key, 'key', this._db._isBuffer)
  if (err)
    throw err

  if (!this._db._isBuffer(key)) key = String(key)
  if (!this._db._isBuffer(value)) value = String(value)

  if (typeof this._put == 'function' )
    this._put(key, value)
  else
    this._operations.push({ type: 'put', key: key, value: value })

  return this
}

AbstractChainedBatch.prototype.del = function (key) {
  this._checkWritten()

  var err = this._db._checkKey(key, 'key', this._db._isBuffer)
  if (err) throw err

  if (!this._db._isBuffer(key)) key = String(key)

  if (typeof this._del == 'function' )
    this._del(key)
  else
    this._operations.push({ type: 'del', key: key })

  return this
}

AbstractChainedBatch.prototype.clear = function () {
  this._checkWritten()

  this._operations = []

  if (typeof this._clear == 'function' )
    this._clear()

  return this
}

AbstractChainedBatch.prototype.write = function (options, callback) {
  this._checkWritten()

  if (typeof options == 'function')
    callback = options
  if (typeof callback != 'function')
    throw new Error('write() requires a callback argument')
  if (typeof options != 'object')
    options = {}

  this._written = true

  if (typeof this._write == 'function' )
    return this._write(callback)

  if (typeof this._db._batch == 'function')
    return this._db._batch(this._operations, options, callback)

  process.nextTick(callback)
}

module.exports = AbstractChainedBatch
}).call(this,require('_process'))
},{"_process":113}],13:[function(require,module,exports){
arguments[4][3][0].apply(exports,arguments)
},{"_process":113,"dup":3}],14:[function(require,module,exports){
(function (Buffer,process){
/* Copyright (c) 2013 Rod Vagg, MIT License */

var xtend                = require('xtend')
  , AbstractIterator     = require('./abstract-iterator')
  , AbstractChainedBatch = require('./abstract-chained-batch')

function AbstractLevelDOWN (location) {
  if (!arguments.length || location === undefined)
    throw new Error('constructor requires at least a location argument')

  if (typeof location != 'string')
    throw new Error('constructor requires a location string argument')

  this.location = location
  this.status = 'new'
}

AbstractLevelDOWN.prototype.open = function (options, callback) {
  var self      = this
    , oldStatus = this.status

  if (typeof options == 'function')
    callback = options

  if (typeof callback != 'function')
    throw new Error('open() requires a callback argument')

  if (typeof options != 'object')
    options = {}

  options.createIfMissing = options.createIfMissing != false
  options.errorIfExists = !!options.errorIfExists

  if (typeof this._open == 'function') {
    this.status = 'opening'
    this._open(options, function (err) {
      if (err) {
        self.status = oldStatus
        return callback(err)
      }
      self.status = 'open'
      callback()
    })
  } else {
    this.status = 'open'
    process.nextTick(callback)
  }
}

AbstractLevelDOWN.prototype.close = function (callback) {
  var self      = this
    , oldStatus = this.status

  if (typeof callback != 'function')
    throw new Error('close() requires a callback argument')

  if (typeof this._close == 'function') {
    this.status = 'closing'
    this._close(function (err) {
      if (err) {
        self.status = oldStatus
        return callback(err)
      }
      self.status = 'closed'
      callback()
    })
  } else {
    this.status = 'closed'
    process.nextTick(callback)
  }
}

AbstractLevelDOWN.prototype.get = function (key, options, callback) {
  var err

  if (typeof options == 'function')
    callback = options

  if (typeof callback != 'function')
    throw new Error('get() requires a callback argument')

  if (err = this._checkKey(key, 'key', this._isBuffer))
    return callback(err)

  if (!this._isBuffer(key))
    key = String(key)

  if (typeof options != 'object')
    options = {}

  options.asBuffer = options.asBuffer != false

  if (typeof this._get == 'function')
    return this._get(key, options, callback)

  process.nextTick(function () { callback(new Error('NotFound')) })
}

AbstractLevelDOWN.prototype.put = function (key, value, options, callback) {
  var err

  if (typeof options == 'function')
    callback = options

  if (typeof callback != 'function')
    throw new Error('put() requires a callback argument')

  if (err = this._checkKey(key, 'key', this._isBuffer))
    return callback(err)

  if (!this._isBuffer(key))
    key = String(key)

  // coerce value to string in node, don't touch it in browser
  // (indexeddb can store any JS type)
  if (value != null && !this._isBuffer(value) && !process.browser)
    value = String(value)

  if (typeof options != 'object')
    options = {}

  if (typeof this._put == 'function')
    return this._put(key, value, options, callback)

  process.nextTick(callback)
}

AbstractLevelDOWN.prototype.del = function (key, options, callback) {
  var err

  if (typeof options == 'function')
    callback = options

  if (typeof callback != 'function')
    throw new Error('del() requires a callback argument')

  if (err = this._checkKey(key, 'key', this._isBuffer))
    return callback(err)

  if (!this._isBuffer(key))
    key = String(key)

  if (typeof options != 'object')
    options = {}

  if (typeof this._del == 'function')
    return this._del(key, options, callback)

  process.nextTick(callback)
}

AbstractLevelDOWN.prototype.batch = function (array, options, callback) {
  if (!arguments.length)
    return this._chainedBatch()

  if (typeof options == 'function')
    callback = options

  if (typeof array == 'function')
    callback = array

  if (typeof callback != 'function')
    throw new Error('batch(array) requires a callback argument')

  if (!Array.isArray(array))
    return callback(new Error('batch(array) requires an array argument'))

  if (!options || typeof options != 'object')
    options = {}

  var i = 0
    , l = array.length
    , e
    , err

  for (; i < l; i++) {
    e = array[i]
    if (typeof e != 'object')
      continue

    if (err = this._checkKey(e.type, 'type', this._isBuffer))
      return callback(err)

    if (err = this._checkKey(e.key, 'key', this._isBuffer))
      return callback(err)
  }

  if (typeof this._batch == 'function')
    return this._batch(array, options, callback)

  process.nextTick(callback)
}

//TODO: remove from here, not a necessary primitive
AbstractLevelDOWN.prototype.approximateSize = function (start, end, callback) {
  if (   start == null
      || end == null
      || typeof start == 'function'
      || typeof end == 'function') {
    throw new Error('approximateSize() requires valid `start`, `end` and `callback` arguments')
  }

  if (typeof callback != 'function')
    throw new Error('approximateSize() requires a callback argument')

  if (!this._isBuffer(start))
    start = String(start)

  if (!this._isBuffer(end))
    end = String(end)

  if (typeof this._approximateSize == 'function')
    return this._approximateSize(start, end, callback)

  process.nextTick(function () {
    callback(null, 0)
  })
}

AbstractLevelDOWN.prototype._setupIteratorOptions = function (options) {
  var self = this

  options = xtend(options)

  ;[ 'start', 'end', 'gt', 'gte', 'lt', 'lte' ].forEach(function (o) {
    if (options[o] && self._isBuffer(options[o]) && options[o].length === 0)
      delete options[o]
  })

  options.reverse = !!options.reverse
  options.keys = options.keys != false
  options.values = options.values != false
  options.limit = 'limit' in options ? options.limit : -1
  options.keyAsBuffer = options.keyAsBuffer != false
  options.valueAsBuffer = options.valueAsBuffer != false

  return options
}

AbstractLevelDOWN.prototype.iterator = function (options) {
  if (typeof options != 'object')
    options = {}

  options = this._setupIteratorOptions(options)

  if (typeof this._iterator == 'function')
    return this._iterator(options)

  return new AbstractIterator(this)
}

AbstractLevelDOWN.prototype._chainedBatch = function () {
  return new AbstractChainedBatch(this)
}

AbstractLevelDOWN.prototype._isBuffer = function (obj) {
  return Buffer.isBuffer(obj)
}

AbstractLevelDOWN.prototype._checkKey = function (obj, type) {

  if (obj === null || obj === undefined)
    return new Error(type + ' cannot be `null` or `undefined`')

  if (this._isBuffer(obj)) {
    if (obj.length === 0)
      return new Error(type + ' cannot be an empty Buffer')
  } else if (String(obj) === '')
    return new Error(type + ' cannot be an empty String')
}

module.exports = AbstractLevelDOWN

}).call(this,{"isBuffer":require("../../../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js")},require('_process'))
},{"../../../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js":110,"./abstract-chained-batch":12,"./abstract-iterator":13,"_process":113,"xtend":17}],15:[function(require,module,exports){
exports.AbstractLevelDOWN    = require('./abstract-leveldown')
exports.AbstractIterator     = require('./abstract-iterator')
exports.AbstractChainedBatch = require('./abstract-chained-batch')
exports.isLevelDOWN          = require('./is-leveldown')

},{"./abstract-chained-batch":12,"./abstract-iterator":13,"./abstract-leveldown":14,"./is-leveldown":16}],16:[function(require,module,exports){
var AbstractLevelDOWN = require('./abstract-leveldown')

function isLevelDOWN (db) {
  if (!db || typeof db !== 'object')
    return false
  return Object.keys(AbstractLevelDOWN.prototype).filter(function (name) {
    // TODO remove approximateSize check when method is gone
    return name[0] != '_' && name != 'approximateSize'
  }).every(function (name) {
    return typeof db[name] == 'function'
  })
}

module.exports = isLevelDOWN

},{"./abstract-leveldown":14}],17:[function(require,module,exports){
module.exports = extend

var hasOwnProperty = Object.prototype.hasOwnProperty;

function extend() {
    var target = {}

    for (var i = 0; i < arguments.length; i++) {
        var source = arguments[i]

        for (var key in source) {
            if (hasOwnProperty.call(source, key)) {
                target[key] = source[key]
            }
        }
    }

    return target
}

},{}],18:[function(require,module,exports){
/**
 * Copyright (c) 2013 Petka Antonov
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:</p>
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
"use strict";
function Deque(capacity) {
    this._capacity = getCapacity(capacity);
    this._length = 0;
    this._front = 0;
    if (isArray(capacity)) {
        var len = capacity.length;
        for (var i = 0; i < len; ++i) {
            this[i] = capacity[i];
        }
        this._length = len;
    }
}

Deque.prototype.toArray = function Deque$toArray() {
    var len = this._length;
    var ret = new Array(len);
    var front = this._front;
    var capacity = this._capacity;
    for (var j = 0; j < len; ++j) {
        ret[j] = this[(front + j) & (capacity - 1)];
    }
    return ret;
};

Deque.prototype.push = function Deque$push(item) {
    var argsLength = arguments.length;
    var length = this._length;
    if (argsLength > 1) {
        var capacity = this._capacity;
        if (length + argsLength > capacity) {
            for (var i = 0; i < argsLength; ++i) {
                this._checkCapacity(length + 1);
                var j = (this._front + length) & (this._capacity - 1);
                this[j] = arguments[i];
                length++;
                this._length = length;
            }
            return length;
        }
        else {
            var j = this._front;
            for (var i = 0; i < argsLength; ++i) {
                this[(j + length) & (capacity - 1)] = arguments[i];
                j++;
            }
            this._length = length + argsLength;
            return length + argsLength;
        }

    }

    if (argsLength === 0) return length;

    this._checkCapacity(length + 1);
    var i = (this._front + length) & (this._capacity - 1);
    this[i] = item;
    this._length = length + 1;
    return length + 1;
};

Deque.prototype.pop = function Deque$pop() {
    var length = this._length;
    if (length === 0) {
        return void 0;
    }
    var i = (this._front + length - 1) & (this._capacity - 1);
    var ret = this[i];
    this[i] = void 0;
    this._length = length - 1;
    return ret;
};

Deque.prototype.shift = function Deque$shift() {
    var length = this._length;
    if (length === 0) {
        return void 0;
    }
    var front = this._front;
    var ret = this[front];
    this[front] = void 0;
    this._front = (front + 1) & (this._capacity - 1);
    this._length = length - 1;
    return ret;
};

Deque.prototype.unshift = function Deque$unshift(item) {
    var length = this._length;
    var argsLength = arguments.length;


    if (argsLength > 1) {
        var capacity = this._capacity;
        if (length + argsLength > capacity) {
            for (var i = argsLength - 1; i >= 0; i--) {
                this._checkCapacity(length + 1);
                var capacity = this._capacity;
                var j = (((( this._front - 1 ) &
                    ( capacity - 1) ) ^ capacity ) - capacity );
                this[j] = arguments[i];
                length++;
                this._length = length;
                this._front = j;
            }
            return length;
        }
        else {
            var front = this._front;
            for (var i = argsLength - 1; i >= 0; i--) {
                var j = (((( front - 1 ) &
                    ( capacity - 1) ) ^ capacity ) - capacity );
                this[j] = arguments[i];
                front = j;
            }
            this._front = front;
            this._length = length + argsLength;
            return length + argsLength;
        }
    }

    if (argsLength === 0) return length;

    this._checkCapacity(length + 1);
    var capacity = this._capacity;
    var i = (((( this._front - 1 ) &
        ( capacity - 1) ) ^ capacity ) - capacity );
    this[i] = item;
    this._length = length + 1;
    this._front = i;
    return length + 1;
};

Deque.prototype.peekBack = function Deque$peekBack() {
    var length = this._length;
    if (length === 0) {
        return void 0;
    }
    var index = (this._front + length - 1) & (this._capacity - 1);
    return this[index];
};

Deque.prototype.peekFront = function Deque$peekFront() {
    if (this._length === 0) {
        return void 0;
    }
    return this[this._front];
};

Deque.prototype.get = function Deque$get(index) {
    var i = index;
    if ((i !== (i | 0))) {
        return void 0;
    }
    var len = this._length;
    if (i < 0) {
        i = i + len;
    }
    if (i < 0 || i >= len) {
        return void 0;
    }
    return this[(this._front + i) & (this._capacity - 1)];
};

Deque.prototype.isEmpty = function Deque$isEmpty() {
    return this._length === 0;
};

Deque.prototype.clear = function Deque$clear() {
    var len = this._length;
    var front = this._front;
    var capacity = this._capacity;
    for (var j = 0; j < len; ++j) {
        this[(front + j) & (capacity - 1)] = void 0;
    }
    this._length = 0;
    this._front = 0;
};

Deque.prototype.toString = function Deque$toString() {
    return this.toArray().toString();
};

Deque.prototype.valueOf = Deque.prototype.toString;
Deque.prototype.removeFront = Deque.prototype.shift;
Deque.prototype.removeBack = Deque.prototype.pop;
Deque.prototype.insertFront = Deque.prototype.unshift;
Deque.prototype.insertBack = Deque.prototype.push;
Deque.prototype.enqueue = Deque.prototype.push;
Deque.prototype.dequeue = Deque.prototype.shift;
Deque.prototype.toJSON = Deque.prototype.toArray;

Object.defineProperty(Deque.prototype, "length", {
    get: function() {
        return this._length;
    },
    set: function() {
        throw new RangeError("");
    }
});

Deque.prototype._checkCapacity = function Deque$_checkCapacity(size) {
    if (this._capacity < size) {
        this._resizeTo(getCapacity(this._capacity * 1.5 + 16));
    }
};

Deque.prototype._resizeTo = function Deque$_resizeTo(capacity) {
    var oldCapacity = this._capacity;
    this._capacity = capacity;
    var front = this._front;
    var length = this._length;
    if (front + length > oldCapacity) {
        var moveItemsCount = (front + length) & (oldCapacity - 1);
        arrayMove(this, 0, this, oldCapacity, moveItemsCount);
    }
};


var isArray = Array.isArray;

function arrayMove(src, srcIndex, dst, dstIndex, len) {
    for (var j = 0; j < len; ++j) {
        dst[j + dstIndex] = src[j + srcIndex];
        src[j + srcIndex] = void 0;
    }
}

function pow2AtLeast(n) {
    n = n >>> 0;
    n = n - 1;
    n = n | (n >> 1);
    n = n | (n >> 2);
    n = n | (n >> 4);
    n = n | (n >> 8);
    n = n | (n >> 16);
    return n + 1;
}

function getCapacity(capacity) {
    if (typeof capacity !== "number") {
        if (isArray(capacity)) {
            capacity = capacity.length;
        }
        else {
            return 16;
        }
    }
    return pow2AtLeast(
        Math.min(
            Math.max(16, capacity), 1073741824)
    );
}

module.exports = Deque;

},{}],19:[function(require,module,exports){
var prr = require('prr')

function init (type, message, cause) {
  prr(this, {
      type    : type
    , name    : type
      // can be passed just a 'cause'
    , cause   : typeof message != 'string' ? message : cause
    , message : !!message && typeof message != 'string' ? message.message : message

  }, 'ewr')
}

// generic prototype, not intended to be actually used - helpful for `instanceof`
function CustomError (message, cause) {
  Error.call(this)
  if (Error.captureStackTrace)
    Error.captureStackTrace(this, arguments.callee)
  init.call(this, 'CustomError', message, cause)
}

CustomError.prototype = new Error()

function createError (errno, type, proto) {
  var err = function (message, cause) {
    init.call(this, type, message, cause)
    //TODO: the specificity here is stupid, errno should be available everywhere
    if (type == 'FilesystemError') {
      this.code    = this.cause.code
      this.path    = this.cause.path
      this.errno   = this.cause.errno
      this.message =
        (errno.errno[this.cause.errno]
          ? errno.errno[this.cause.errno].description
          : this.cause.message)
        + (this.cause.path ? ' [' + this.cause.path + ']' : '')
    }
    Error.call(this)
    if (Error.captureStackTrace)
      Error.captureStackTrace(this, arguments.callee)
  }
  err.prototype = !!proto ? new proto() : new CustomError()
  return err
}

module.exports = function (errno) {
  var ce = function (type, proto) {
    return createError(errno, type, proto)
  }
  return {
      CustomError     : CustomError
    , FilesystemError : ce('FilesystemError')
    , createError     : ce
  }
}

},{"prr":21}],20:[function(require,module,exports){
var all = module.exports.all = [
  {
    errno: -2,
    code: 'ENOENT',
    description: 'no such file or directory'
  },
  {
    errno: -1,
    code: 'UNKNOWN',
    description: 'unknown error'
  },
  {
    errno: 0,
    code: 'OK',
    description: 'success'
  },
  {
    errno: 1,
    code: 'EOF',
    description: 'end of file'
  },
  {
    errno: 2,
    code: 'EADDRINFO',
    description: 'getaddrinfo error'
  },
  {
    errno: 3,
    code: 'EACCES',
    description: 'permission denied'
  },
  {
    errno: 4,
    code: 'EAGAIN',
    description: 'resource temporarily unavailable'
  },
  {
    errno: 5,
    code: 'EADDRINUSE',
    description: 'address already in use'
  },
  {
    errno: 6,
    code: 'EADDRNOTAVAIL',
    description: 'address not available'
  },
  {
    errno: 7,
    code: 'EAFNOSUPPORT',
    description: 'address family not supported'
  },
  {
    errno: 8,
    code: 'EALREADY',
    description: 'connection already in progress'
  },
  {
    errno: 9,
    code: 'EBADF',
    description: 'bad file descriptor'
  },
  {
    errno: 10,
    code: 'EBUSY',
    description: 'resource busy or locked'
  },
  {
    errno: 11,
    code: 'ECONNABORTED',
    description: 'software caused connection abort'
  },
  {
    errno: 12,
    code: 'ECONNREFUSED',
    description: 'connection refused'
  },
  {
    errno: 13,
    code: 'ECONNRESET',
    description: 'connection reset by peer'
  },
  {
    errno: 14,
    code: 'EDESTADDRREQ',
    description: 'destination address required'
  },
  {
    errno: 15,
    code: 'EFAULT',
    description: 'bad address in system call argument'
  },
  {
    errno: 16,
    code: 'EHOSTUNREACH',
    description: 'host is unreachable'
  },
  {
    errno: 17,
    code: 'EINTR',
    description: 'interrupted system call'
  },
  {
    errno: 18,
    code: 'EINVAL',
    description: 'invalid argument'
  },
  {
    errno: 19,
    code: 'EISCONN',
    description: 'socket is already connected'
  },
  {
    errno: 20,
    code: 'EMFILE',
    description: 'too many open files'
  },
  {
    errno: 21,
    code: 'EMSGSIZE',
    description: 'message too long'
  },
  {
    errno: 22,
    code: 'ENETDOWN',
    description: 'network is down'
  },
  {
    errno: 23,
    code: 'ENETUNREACH',
    description: 'network is unreachable'
  },
  {
    errno: 24,
    code: 'ENFILE',
    description: 'file table overflow'
  },
  {
    errno: 25,
    code: 'ENOBUFS',
    description: 'no buffer space available'
  },
  {
    errno: 26,
    code: 'ENOMEM',
    description: 'not enough memory'
  },
  {
    errno: 27,
    code: 'ENOTDIR',
    description: 'not a directory'
  },
  {
    errno: 28,
    code: 'EISDIR',
    description: 'illegal operation on a directory'
  },
  {
    errno: 29,
    code: 'ENONET',
    description: 'machine is not on the network'
  },
  {
    errno: 31,
    code: 'ENOTCONN',
    description: 'socket is not connected'
  },
  {
    errno: 32,
    code: 'ENOTSOCK',
    description: 'socket operation on non-socket'
  },
  {
    errno: 33,
    code: 'ENOTSUP',
    description: 'operation not supported on socket'
  },
  {
    errno: 34,
    code: 'ENOENT',
    description: 'no such file or directory'
  },
  {
    errno: 35,
    code: 'ENOSYS',
    description: 'function not implemented'
  },
  {
    errno: 36,
    code: 'EPIPE',
    description: 'broken pipe'
  },
  {
    errno: 37,
    code: 'EPROTO',
    description: 'protocol error'
  },
  {
    errno: 38,
    code: 'EPROTONOSUPPORT',
    description: 'protocol not supported'
  },
  {
    errno: 39,
    code: 'EPROTOTYPE',
    description: 'protocol wrong type for socket'
  },
  {
    errno: 40,
    code: 'ETIMEDOUT',
    description: 'connection timed out'
  },
  {
    errno: 41,
    code: 'ECHARSET',
    description: 'invalid Unicode character'
  },
  {
    errno: 42,
    code: 'EAIFAMNOSUPPORT',
    description: 'address family for hostname not supported'
  },
  {
    errno: 44,
    code: 'EAISERVICE',
    description: 'servname not supported for ai_socktype'
  },
  {
    errno: 45,
    code: 'EAISOCKTYPE',
    description: 'ai_socktype not supported'
  },
  {
    errno: 46,
    code: 'ESHUTDOWN',
    description: 'cannot send after transport endpoint shutdown'
  },
  {
    errno: 47,
    code: 'EEXIST',
    description: 'file already exists'
  },
  {
    errno: 48,
    code: 'ESRCH',
    description: 'no such process'
  },
  {
    errno: 49,
    code: 'ENAMETOOLONG',
    description: 'name too long'
  },
  {
    errno: 50,
    code: 'EPERM',
    description: 'operation not permitted'
  },
  {
    errno: 51,
    code: 'ELOOP',
    description: 'too many symbolic links encountered'
  },
  {
    errno: 52,
    code: 'EXDEV',
    description: 'cross-device link not permitted'
  },
  {
    errno: 53,
    code: 'ENOTEMPTY',
    description: 'directory not empty'
  },
  {
    errno: 54,
    code: 'ENOSPC',
    description: 'no space left on device'
  },
  {
    errno: 55,
    code: 'EIO',
    description: 'i/o error'
  },
  {
    errno: 56,
    code: 'EROFS',
    description: 'read-only file system'
  },
  {
    errno: 57,
    code: 'ENODEV',
    description: 'no such device'
  },
  {
    errno: 58,
    code: 'ESPIPE',
    description: 'invalid seek'
  },
  {
    errno: 59,
    code: 'ECANCELED',
    description: 'operation canceled'
  }
]

module.exports.errno = {}
module.exports.code = {}

all.forEach(function (error) {
  module.exports.errno[error.errno] = error
  module.exports.code[error.code] = error
})

module.exports.custom = require('./custom')(module.exports)
module.exports.create = module.exports.custom.createError

},{"./custom":19}],21:[function(require,module,exports){
/*!
  * prr
  * (c) 2013 Rod Vagg <rod@vagg.org>
  * https://github.com/rvagg/prr
  * License: MIT
  */

(function (name, context, definition) {
  if (typeof module != 'undefined' && module.exports)
    module.exports = definition()
  else
    context[name] = definition()
})('prr', this, function() {

  var setProperty = typeof Object.defineProperty == 'function'
      ? function (obj, key, options) {
          Object.defineProperty(obj, key, options)
          return obj
        }
      : function (obj, key, options) { // < es5
          obj[key] = options.value
          return obj
        }

    , makeOptions = function (value, options) {
        var oo = typeof options == 'object'
          , os = !oo && typeof options == 'string'
          , op = function (p) {
              return oo
                ? !!options[p]
                : os
                  ? options.indexOf(p[0]) > -1
                  : false
            }

        return {
            enumerable   : op('enumerable')
          , configurable : op('configurable')
          , writable     : op('writable')
          , value        : value
        }
      }

    , prr = function (obj, key, value, options) {
        var k

        options = makeOptions(value, options)

        if (typeof key == 'object') {
          for (k in key) {
            if (Object.hasOwnProperty.call(key, k)) {
              options.value = key[k]
              setProperty(obj, k, options)
            }
          }
          return obj
        }

        return setProperty(obj, key, options)
      }

  return prr
})
},{}],22:[function(require,module,exports){
(function (root, factory) {
  /* istanbul ignore next */
  if (typeof define === 'function' && define.amd) {
    define([], factory)
  } else if (typeof exports === 'object') {
    module.exports = factory()
  } else {
    root.PromisePool = factory()
    // Legacy API
    root.promisePool = root.PromisePool
  }
})(this, function () {
  'use strict'

  var EventTarget = function () {
    this._listeners = {}
  }

  EventTarget.prototype.addEventListener = function (type, listener) {
    this._listeners[type] = this._listeners[type] || []
    if (this._listeners[type].indexOf(listener) < 0) {
      this._listeners[type].push(listener)
    }
  }

  EventTarget.prototype.removeEventListener = function (type, listener) {
    if (this._listeners[type]) {
      var p = this._listeners[type].indexOf(listener)
      if (p >= 0) {
        this._listeners[type].splice(p, 1)
      }
    }
  }

  EventTarget.prototype.dispatchEvent = function (evt) {
    if (this._listeners[evt.type] && this._listeners[evt.type].length) {
      var listeners = this._listeners[evt.type].slice()
      for (var i = 0, l = listeners.length; i < l; ++i) {
        listeners[i].call(this, evt)
      }
    }
  }

  var isGenerator = function (func) {
    return (typeof func.constructor === 'function' &&
      func.constructor.name === 'GeneratorFunction')
  }

  var functionToIterator = function (func) {
    return {
      next: function () {
        var promise = func()
        return promise ? {value: promise} : {done: true}
      }
    }
  }

  var promiseToIterator = function (promise) {
    var called = false
    return {
      next: function () {
        if (called) {
          return {done: true}
        }
        called = true
        return {value: promise}
      }
    }
  }

  var toIterator = function (obj, Promise) {
    var type = typeof obj
    if (type === 'object') {
      if (typeof obj.next === 'function') {
        return obj
      }
      /* istanbul ignore else */
      if (typeof obj.then === 'function') {
        return promiseToIterator(obj)
      }
    }
    if (type === 'function') {
      return isGenerator(obj) ? obj() : functionToIterator(obj)
    }
    return promiseToIterator(Promise.resolve(obj))
  }

  var PromisePoolEvent = function (target, type, data) {
    this.target = target
    this.type = type
    this.data = data
  }

  var PromisePool = function (source, concurrency, options) {
    EventTarget.call(this)
    if (typeof concurrency !== 'number' ||
        Math.floor(concurrency) !== concurrency ||
        concurrency < 1) {
      throw new Error('Invalid concurrency')
    }
    this._concurrency = concurrency
    this._options = options || {}
    this._options.promise = this._options.promise || Promise
    this._iterator = toIterator(source, this._options.promise)
    this._done = false
    this._size = 0
    this._promise = null
    this._callbacks = null
  }
  PromisePool.prototype = new EventTarget()
  PromisePool.prototype.constructor = PromisePool

  PromisePool.prototype.concurrency = function (value) {
    if (typeof value !== 'undefined') {
      this._concurrency = value
      if (this.active()) {
        this._proceed()
      }
    }
    return this._concurrency
  }

  PromisePool.prototype.size = function () {
    return this._size
  }

  PromisePool.prototype.active = function () {
    return !!this._promise
  }

  PromisePool.prototype.promise = function () {
    return this._promise
  }

  PromisePool.prototype.start = function () {
    var that = this
    var Promise = this._options.promise
    this._promise = new Promise(function (resolve, reject) {
      that._callbacks = {
        reject: reject,
        resolve: resolve
      }
      that._proceed()
    })
    return this._promise
  }

  PromisePool.prototype._fireEvent = function (type, data) {
    this.dispatchEvent(new PromisePoolEvent(this, type, data))
  }

  PromisePool.prototype._settle = function (error) {
    if (error) {
      this._callbacks.reject(error)
    } else {
      this._callbacks.resolve()
    }
    this._promise = null
    this._callbacks = null
  }

  PromisePool.prototype._onPooledPromiseFulfilled = function (promise, result) {
    this._size--
    if (this.active()) {
      this._fireEvent('fulfilled', {
        promise: promise,
        result: result
      })
      this._proceed()
    }
  }

  PromisePool.prototype._onPooledPromiseRejected = function (promise, error) {
    this._size--
    if (this.active()) {
      this._fireEvent('rejected', {
        promise: promise,
        error: error
      })
      this._settle(error || new Error('Unknown error'))
    }
  }

  PromisePool.prototype._trackPromise = function (promise) {
    var that = this
    promise
      .then(function (result) {
        that._onPooledPromiseFulfilled(promise, result)
      }, function (error) {
        that._onPooledPromiseRejected(promise, error)
      })['catch'](function (err) {
        that._settle(new Error('Promise processing failed: ' + err))
      })
  }

  PromisePool.prototype._proceed = function () {
    if (!this._done) {
      var result = null
      while (this._size < this._concurrency &&
          !(result = this._iterator.next()).done) {
        this._size++
        this._trackPromise(result.value)
      }
      this._done = (result === null || !!result.done)
    }
    if (this._done && this._size === 0) {
      this._settle()
    }
  }

  PromisePool.PromisePoolEvent = PromisePoolEvent
  // Legacy API
  PromisePool.PromisePool = PromisePool

  return PromisePool
})

},{}],23:[function(require,module,exports){
"use strict"

module.exports = createRBTree

var RED   = 0
var BLACK = 1

function RBNode(color, key, value, left, right, count) {
  this._color = color
  this.key = key
  this.value = value
  this.left = left
  this.right = right
  this._count = count
}

function cloneNode(node) {
  return new RBNode(node._color, node.key, node.value, node.left, node.right, node._count)
}

function repaint(color, node) {
  return new RBNode(color, node.key, node.value, node.left, node.right, node._count)
}

function recount(node) {
  node._count = 1 + (node.left ? node.left._count : 0) + (node.right ? node.right._count : 0)
}

function RedBlackTree(compare, root) {
  this._compare = compare
  this.root = root
}

var proto = RedBlackTree.prototype

Object.defineProperty(proto, "keys", {
  get: function() {
    var result = []
    this.forEach(function(k,v) {
      result.push(k)
    })
    return result
  }
})

Object.defineProperty(proto, "values", {
  get: function() {
    var result = []
    this.forEach(function(k,v) {
      result.push(v)
    })
    return result
  }
})

//Returns the number of nodes in the tree
Object.defineProperty(proto, "length", {
  get: function() {
    if(this.root) {
      return this.root._count
    }
    return 0
  }
})

//Insert a new item into the tree
proto.insert = function(key, value) {
  var cmp = this._compare
  //Find point to insert new node at
  var n = this.root
  var n_stack = []
  var d_stack = []
  while(n) {
    var d = cmp(key, n.key)
    n_stack.push(n)
    d_stack.push(d)
    if(d <= 0) {
      n = n.left
    } else {
      n = n.right
    }
  }
  //Rebuild path to leaf node
  n_stack.push(new RBNode(RED, key, value, null, null, 1))
  for(var s=n_stack.length-2; s>=0; --s) {
    var n = n_stack[s]
    if(d_stack[s] <= 0) {
      n_stack[s] = new RBNode(n._color, n.key, n.value, n_stack[s+1], n.right, n._count+1)
    } else {
      n_stack[s] = new RBNode(n._color, n.key, n.value, n.left, n_stack[s+1], n._count+1)
    }
  }
  //Rebalance tree using rotations
  //console.log("start insert", key, d_stack)
  for(var s=n_stack.length-1; s>1; --s) {
    var p = n_stack[s-1]
    var n = n_stack[s]
    if(p._color === BLACK || n._color === BLACK) {
      break
    }
    var pp = n_stack[s-2]
    if(pp.left === p) {
      if(p.left === n) {
        var y = pp.right
        if(y && y._color === RED) {
          //console.log("LLr")
          p._color = BLACK
          pp.right = repaint(BLACK, y)
          pp._color = RED
          s -= 1
        } else {
          //console.log("LLb")
          pp._color = RED
          pp.left = p.right
          p._color = BLACK
          p.right = pp
          n_stack[s-2] = p
          n_stack[s-1] = n
          recount(pp)
          recount(p)
          if(s >= 3) {
            var ppp = n_stack[s-3]
            if(ppp.left === pp) {
              ppp.left = p
            } else {
              ppp.right = p
            }
          }
          break
        }
      } else {
        var y = pp.right
        if(y && y._color === RED) {
          //console.log("LRr")
          p._color = BLACK
          pp.right = repaint(BLACK, y)
          pp._color = RED
          s -= 1
        } else {
          //console.log("LRb")
          p.right = n.left
          pp._color = RED
          pp.left = n.right
          n._color = BLACK
          n.left = p
          n.right = pp
          n_stack[s-2] = n
          n_stack[s-1] = p
          recount(pp)
          recount(p)
          recount(n)
          if(s >= 3) {
            var ppp = n_stack[s-3]
            if(ppp.left === pp) {
              ppp.left = n
            } else {
              ppp.right = n
            }
          }
          break
        }
      }
    } else {
      if(p.right === n) {
        var y = pp.left
        if(y && y._color === RED) {
          //console.log("RRr", y.key)
          p._color = BLACK
          pp.left = repaint(BLACK, y)
          pp._color = RED
          s -= 1
        } else {
          //console.log("RRb")
          pp._color = RED
          pp.right = p.left
          p._color = BLACK
          p.left = pp
          n_stack[s-2] = p
          n_stack[s-1] = n
          recount(pp)
          recount(p)
          if(s >= 3) {
            var ppp = n_stack[s-3]
            if(ppp.right === pp) {
              ppp.right = p
            } else {
              ppp.left = p
            }
          }
          break
        }
      } else {
        var y = pp.left
        if(y && y._color === RED) {
          //console.log("RLr")
          p._color = BLACK
          pp.left = repaint(BLACK, y)
          pp._color = RED
          s -= 1
        } else {
          //console.log("RLb")
          p.left = n.right
          pp._color = RED
          pp.right = n.left
          n._color = BLACK
          n.right = p
          n.left = pp
          n_stack[s-2] = n
          n_stack[s-1] = p
          recount(pp)
          recount(p)
          recount(n)
          if(s >= 3) {
            var ppp = n_stack[s-3]
            if(ppp.right === pp) {
              ppp.right = n
            } else {
              ppp.left = n
            }
          }
          break
        }
      }
    }
  }
  //Return new tree
  n_stack[0]._color = BLACK
  return new RedBlackTree(cmp, n_stack[0])
}


//Visit all nodes inorder
function doVisitFull(visit, node) {
  if(node.left) {
    var v = doVisitFull(visit, node.left)
    if(v) { return v }
  }
  var v = visit(node.key, node.value)
  if(v) { return v }
  if(node.right) {
    return doVisitFull(visit, node.right)
  }
}

//Visit half nodes in order
function doVisitHalf(lo, compare, visit, node) {
  var l = compare(lo, node.key)
  if(l <= 0) {
    if(node.left) {
      var v = doVisitHalf(lo, compare, visit, node.left)
      if(v) { return v }
    }
    var v = visit(node.key, node.value)
    if(v) { return v }
  }
  if(node.right) {
    return doVisitHalf(lo, compare, visit, node.right)
  }
}

//Visit all nodes within a range
function doVisit(lo, hi, compare, visit, node) {
  var l = compare(lo, node.key)
  var h = compare(hi, node.key)
  var v
  if(l <= 0) {
    if(node.left) {
      v = doVisit(lo, hi, compare, visit, node.left)
      if(v) { return v }
    }
    if(h > 0) {
      v = visit(node.key, node.value)
      if(v) { return v }
    }
  }
  if(h > 0 && node.right) {
    return doVisit(lo, hi, compare, visit, node.right)
  }
}


proto.forEach = function rbTreeForEach(visit, lo, hi) {
  if(!this.root) {
    return
  }
  switch(arguments.length) {
    case 1:
      return doVisitFull(visit, this.root)
    break

    case 2:
      return doVisitHalf(lo, this._compare, visit, this.root)
    break

    case 3:
      if(this._compare(lo, hi) >= 0) {
        return
      }
      return doVisit(lo, hi, this._compare, visit, this.root)
    break
  }
}

//First item in list
Object.defineProperty(proto, "begin", {
  get: function() {
    var stack = []
    var n = this.root
    while(n) {
      stack.push(n)
      n = n.left
    }
    return new RedBlackTreeIterator(this, stack)
  }
})

//Last item in list
Object.defineProperty(proto, "end", {
  get: function() {
    var stack = []
    var n = this.root
    while(n) {
      stack.push(n)
      n = n.right
    }
    return new RedBlackTreeIterator(this, stack)
  }
})

//Find the ith item in the tree
proto.at = function(idx) {
  if(idx < 0) {
    return new RedBlackTreeIterator(this, [])
  }
  var n = this.root
  var stack = []
  while(true) {
    stack.push(n)
    if(n.left) {
      if(idx < n.left._count) {
        n = n.left
        continue
      }
      idx -= n.left._count
    }
    if(!idx) {
      return new RedBlackTreeIterator(this, stack)
    }
    idx -= 1
    if(n.right) {
      if(idx >= n.right._count) {
        break
      }
      n = n.right
    } else {
      break
    }
  }
  return new RedBlackTreeIterator(this, [])
}

proto.ge = function(key) {
  var cmp = this._compare
  var n = this.root
  var stack = []
  var last_ptr = 0
  while(n) {
    var d = cmp(key, n.key)
    stack.push(n)
    if(d <= 0) {
      last_ptr = stack.length
    }
    if(d <= 0) {
      n = n.left
    } else {
      n = n.right
    }
  }
  stack.length = last_ptr
  return new RedBlackTreeIterator(this, stack)
}

proto.gt = function(key) {
  var cmp = this._compare
  var n = this.root
  var stack = []
  var last_ptr = 0
  while(n) {
    var d = cmp(key, n.key)
    stack.push(n)
    if(d < 0) {
      last_ptr = stack.length
    }
    if(d < 0) {
      n = n.left
    } else {
      n = n.right
    }
  }
  stack.length = last_ptr
  return new RedBlackTreeIterator(this, stack)
}

proto.lt = function(key) {
  var cmp = this._compare
  var n = this.root
  var stack = []
  var last_ptr = 0
  while(n) {
    var d = cmp(key, n.key)
    stack.push(n)
    if(d > 0) {
      last_ptr = stack.length
    }
    if(d <= 0) {
      n = n.left
    } else {
      n = n.right
    }
  }
  stack.length = last_ptr
  return new RedBlackTreeIterator(this, stack)
}

proto.le = function(key) {
  var cmp = this._compare
  var n = this.root
  var stack = []
  var last_ptr = 0
  while(n) {
    var d = cmp(key, n.key)
    stack.push(n)
    if(d >= 0) {
      last_ptr = stack.length
    }
    if(d < 0) {
      n = n.left
    } else {
      n = n.right
    }
  }
  stack.length = last_ptr
  return new RedBlackTreeIterator(this, stack)
}

//Finds the item with key if it exists
proto.find = function(key) {
  var cmp = this._compare
  var n = this.root
  var stack = []
  while(n) {
    var d = cmp(key, n.key)
    stack.push(n)
    if(d === 0) {
      return new RedBlackTreeIterator(this, stack)
    }
    if(d <= 0) {
      n = n.left
    } else {
      n = n.right
    }
  }
  return new RedBlackTreeIterator(this, [])
}

//Removes item with key from tree
proto.remove = function(key) {
  var iter = this.find(key)
  if(iter) {
    return iter.remove()
  }
  return this
}

//Returns the item at `key`
proto.get = function(key) {
  var cmp = this._compare
  var n = this.root
  while(n) {
    var d = cmp(key, n.key)
    if(d === 0) {
      return n.value
    }
    if(d <= 0) {
      n = n.left
    } else {
      n = n.right
    }
  }
  return
}

//Iterator for red black tree
function RedBlackTreeIterator(tree, stack) {
  this.tree = tree
  this._stack = stack
}

var iproto = RedBlackTreeIterator.prototype

//Test if iterator is valid
Object.defineProperty(iproto, "valid", {
  get: function() {
    return this._stack.length > 0
  }
})

//Node of the iterator
Object.defineProperty(iproto, "node", {
  get: function() {
    if(this._stack.length > 0) {
      return this._stack[this._stack.length-1]
    }
    return null
  },
  enumerable: true
})

//Makes a copy of an iterator
iproto.clone = function() {
  return new RedBlackTreeIterator(this.tree, this._stack.slice())
}

//Swaps two nodes
function swapNode(n, v) {
  n.key = v.key
  n.value = v.value
  n.left = v.left
  n.right = v.right
  n._color = v._color
  n._count = v._count
}

//Fix up a double black node in a tree
function fixDoubleBlack(stack) {
  var n, p, s, z
  for(var i=stack.length-1; i>=0; --i) {
    n = stack[i]
    if(i === 0) {
      n._color = BLACK
      return
    }
    //console.log("visit node:", n.key, i, stack[i].key, stack[i-1].key)
    p = stack[i-1]
    if(p.left === n) {
      //console.log("left child")
      s = p.right
      if(s.right && s.right._color === RED) {
        //console.log("case 1: right sibling child red")
        s = p.right = cloneNode(s)
        z = s.right = cloneNode(s.right)
        p.right = s.left
        s.left = p
        s.right = z
        s._color = p._color
        n._color = BLACK
        p._color = BLACK
        z._color = BLACK
        recount(p)
        recount(s)
        if(i > 1) {
          var pp = stack[i-2]
          if(pp.left === p) {
            pp.left = s
          } else {
            pp.right = s
          }
        }
        stack[i-1] = s
        return
      } else if(s.left && s.left._color === RED) {
        //console.log("case 1: left sibling child red")
        s = p.right = cloneNode(s)
        z = s.left = cloneNode(s.left)
        p.right = z.left
        s.left = z.right
        z.left = p
        z.right = s
        z._color = p._color
        p._color = BLACK
        s._color = BLACK
        n._color = BLACK
        recount(p)
        recount(s)
        recount(z)
        if(i > 1) {
          var pp = stack[i-2]
          if(pp.left === p) {
            pp.left = z
          } else {
            pp.right = z
          }
        }
        stack[i-1] = z
        return
      }
      if(s._color === BLACK) {
        if(p._color === RED) {
          //console.log("case 2: black sibling, red parent", p.right.value)
          p._color = BLACK
          p.right = repaint(RED, s)
          return
        } else {
          //console.log("case 2: black sibling, black parent", p.right.value)
          p.right = repaint(RED, s)
          continue  
        }
      } else {
        //console.log("case 3: red sibling")
        s = cloneNode(s)
        p.right = s.left
        s.left = p
        s._color = p._color
        p._color = RED
        recount(p)
        recount(s)
        if(i > 1) {
          var pp = stack[i-2]
          if(pp.left === p) {
            pp.left = s
          } else {
            pp.right = s
          }
        }
        stack[i-1] = s
        stack[i] = p
        if(i+1 < stack.length) {
          stack[i+1] = n
        } else {
          stack.push(n)
        }
        i = i+2
      }
    } else {
      //console.log("right child")
      s = p.left
      if(s.left && s.left._color === RED) {
        //console.log("case 1: left sibling child red", p.value, p._color)
        s = p.left = cloneNode(s)
        z = s.left = cloneNode(s.left)
        p.left = s.right
        s.right = p
        s.left = z
        s._color = p._color
        n._color = BLACK
        p._color = BLACK
        z._color = BLACK
        recount(p)
        recount(s)
        if(i > 1) {
          var pp = stack[i-2]
          if(pp.right === p) {
            pp.right = s
          } else {
            pp.left = s
          }
        }
        stack[i-1] = s
        return
      } else if(s.right && s.right._color === RED) {
        //console.log("case 1: right sibling child red")
        s = p.left = cloneNode(s)
        z = s.right = cloneNode(s.right)
        p.left = z.right
        s.right = z.left
        z.right = p
        z.left = s
        z._color = p._color
        p._color = BLACK
        s._color = BLACK
        n._color = BLACK
        recount(p)
        recount(s)
        recount(z)
        if(i > 1) {
          var pp = stack[i-2]
          if(pp.right === p) {
            pp.right = z
          } else {
            pp.left = z
          }
        }
        stack[i-1] = z
        return
      }
      if(s._color === BLACK) {
        if(p._color === RED) {
          //console.log("case 2: black sibling, red parent")
          p._color = BLACK
          p.left = repaint(RED, s)
          return
        } else {
          //console.log("case 2: black sibling, black parent")
          p.left = repaint(RED, s)
          continue  
        }
      } else {
        //console.log("case 3: red sibling")
        s = cloneNode(s)
        p.left = s.right
        s.right = p
        s._color = p._color
        p._color = RED
        recount(p)
        recount(s)
        if(i > 1) {
          var pp = stack[i-2]
          if(pp.right === p) {
            pp.right = s
          } else {
            pp.left = s
          }
        }
        stack[i-1] = s
        stack[i] = p
        if(i+1 < stack.length) {
          stack[i+1] = n
        } else {
          stack.push(n)
        }
        i = i+2
      }
    }
  }
}

//Removes item at iterator from tree
iproto.remove = function() {
  var stack = this._stack
  if(stack.length === 0) {
    return this.tree
  }
  //First copy path to node
  var cstack = new Array(stack.length)
  var n = stack[stack.length-1]
  cstack[cstack.length-1] = new RBNode(n._color, n.key, n.value, n.left, n.right, n._count)
  for(var i=stack.length-2; i>=0; --i) {
    var n = stack[i]
    if(n.left === stack[i+1]) {
      cstack[i] = new RBNode(n._color, n.key, n.value, cstack[i+1], n.right, n._count)
    } else {
      cstack[i] = new RBNode(n._color, n.key, n.value, n.left, cstack[i+1], n._count)
    }
  }

  //Get node
  n = cstack[cstack.length-1]
  //console.log("start remove: ", n.value)

  //If not leaf, then swap with previous node
  if(n.left && n.right) {
    //console.log("moving to leaf")

    //First walk to previous leaf
    var split = cstack.length
    n = n.left
    while(n.right) {
      cstack.push(n)
      n = n.right
    }
    //Copy path to leaf
    var v = cstack[split-1]
    cstack.push(new RBNode(n._color, v.key, v.value, n.left, n.right, n._count))
    cstack[split-1].key = n.key
    cstack[split-1].value = n.value

    //Fix up stack
    for(var i=cstack.length-2; i>=split; --i) {
      n = cstack[i]
      cstack[i] = new RBNode(n._color, n.key, n.value, n.left, cstack[i+1], n._count)
    }
    cstack[split-1].left = cstack[split]
  }
  //console.log("stack=", cstack.map(function(v) { return v.value }))

  //Remove leaf node
  n = cstack[cstack.length-1]
  if(n._color === RED) {
    //Easy case: removing red leaf
    //console.log("RED leaf")
    var p = cstack[cstack.length-2]
    if(p.left === n) {
      p.left = null
    } else if(p.right === n) {
      p.right = null
    }
    cstack.pop()
    for(var i=0; i<cstack.length; ++i) {
      cstack[i]._count--
    }
    return new RedBlackTree(this.tree._compare, cstack[0])
  } else {
    if(n.left || n.right) {
      //Second easy case:  Single child black parent
      //console.log("BLACK single child")
      if(n.left) {
        swapNode(n, n.left)
      } else if(n.right) {
        swapNode(n, n.right)
      }
      //Child must be red, so repaint it black to balance color
      n._color = BLACK
      for(var i=0; i<cstack.length-1; ++i) {
        cstack[i]._count--
      }
      return new RedBlackTree(this.tree._compare, cstack[0])
    } else if(cstack.length === 1) {
      //Third easy case: root
      //console.log("ROOT")
      return new RedBlackTree(this.tree._compare, null)
    } else {
      //Hard case: Repaint n, and then do some nasty stuff
      //console.log("BLACK leaf no children")
      for(var i=0; i<cstack.length; ++i) {
        cstack[i]._count--
      }
      var parent = cstack[cstack.length-2]
      fixDoubleBlack(cstack)
      //Fix up links
      if(parent.left === n) {
        parent.left = null
      } else {
        parent.right = null
      }
    }
  }
  return new RedBlackTree(this.tree._compare, cstack[0])
}

//Returns key
Object.defineProperty(iproto, "key", {
  get: function() {
    if(this._stack.length > 0) {
      return this._stack[this._stack.length-1].key
    }
    return
  },
  enumerable: true
})

//Returns value
Object.defineProperty(iproto, "value", {
  get: function() {
    if(this._stack.length > 0) {
      return this._stack[this._stack.length-1].value
    }
    return
  },
  enumerable: true
})


//Returns the position of this iterator in the sorted list
Object.defineProperty(iproto, "index", {
  get: function() {
    var idx = 0
    var stack = this._stack
    if(stack.length === 0) {
      var r = this.tree.root
      if(r) {
        return r._count
      }
      return 0
    } else if(stack[stack.length-1].left) {
      idx = stack[stack.length-1].left._count
    }
    for(var s=stack.length-2; s>=0; --s) {
      if(stack[s+1] === stack[s].right) {
        ++idx
        if(stack[s].left) {
          idx += stack[s].left._count
        }
      }
    }
    return idx
  },
  enumerable: true
})

//Advances iterator to next element in list
iproto.next = function() {
  var stack = this._stack
  if(stack.length === 0) {
    return
  }
  var n = stack[stack.length-1]
  if(n.right) {
    n = n.right
    while(n) {
      stack.push(n)
      n = n.left
    }
  } else {
    stack.pop()
    while(stack.length > 0 && stack[stack.length-1].right === n) {
      n = stack[stack.length-1]
      stack.pop()
    }
  }
}

//Checks if iterator is at end of tree
Object.defineProperty(iproto, "hasNext", {
  get: function() {
    var stack = this._stack
    if(stack.length === 0) {
      return false
    }
    if(stack[stack.length-1].right) {
      return true
    }
    for(var s=stack.length-1; s>0; --s) {
      if(stack[s-1].left === stack[s]) {
        return true
      }
    }
    return false
  }
})

//Update value
iproto.update = function(value) {
  var stack = this._stack
  if(stack.length === 0) {
    throw new Error("Can't update empty node!")
  }
  var cstack = new Array(stack.length)
  var n = stack[stack.length-1]
  cstack[cstack.length-1] = new RBNode(n._color, n.key, value, n.left, n.right, n._count)
  for(var i=stack.length-2; i>=0; --i) {
    n = stack[i]
    if(n.left === stack[i+1]) {
      cstack[i] = new RBNode(n._color, n.key, n.value, cstack[i+1], n.right, n._count)
    } else {
      cstack[i] = new RBNode(n._color, n.key, n.value, n.left, cstack[i+1], n._count)
    }
  }
  return new RedBlackTree(this.tree._compare, cstack[0])
}

//Moves iterator backward one element
iproto.prev = function() {
  var stack = this._stack
  if(stack.length === 0) {
    return
  }
  var n = stack[stack.length-1]
  if(n.left) {
    n = n.left
    while(n) {
      stack.push(n)
      n = n.right
    }
  } else {
    stack.pop()
    while(stack.length > 0 && stack[stack.length-1].left === n) {
      n = stack[stack.length-1]
      stack.pop()
    }
  }
}

//Checks if iterator is at start of tree
Object.defineProperty(iproto, "hasPrev", {
  get: function() {
    var stack = this._stack
    if(stack.length === 0) {
      return false
    }
    if(stack[stack.length-1].left) {
      return true
    }
    for(var s=stack.length-1; s>0; --s) {
      if(stack[s-1].right === stack[s]) {
        return true
      }
    }
    return false
  }
})

//Default comparison function
function defaultCompare(a, b) {
  if(a < b) {
    return -1
  }
  if(a > b) {
    return 1
  }
  return 0
}

//Build a tree
function createRBTree(compare) {
  return new RedBlackTree(compare || defaultCompare, null)
}
},{}],24:[function(require,module,exports){
/**
 * # hasLocalStorage()
 *
 * returns `true` or `false` depending on whether localStorage is supported or not.
 * Beware that some browsers like Safari do not support localStorage in private mode.
 *
 * inspired by this cappuccino commit
 * https://github.com/cappuccino/cappuccino/commit/063b05d9643c35b303568a28809e4eb3224f71ec
 *
 * @returns {Boolean}
 */
function hasLocalStorage() {
  try {

    // we've to put this in here. I've seen Firefox throwing `Security error: 1000`
    // when cookies have been disabled
    if (typeof localStorage === 'undefined') {
      return false;
    }

    // Just because localStorage exists does not mean it works. In particular it might be disabled
    // as it is when Safari's private browsing mode is active.
    localStorage.setItem('Storage-Test', '1');

    // that should not happen ...
    if (localStorage.getItem('Storage-Test') !== '1') {
      return false;
    }

    // okay, let's clean up if we got here.
    localStorage.removeItem('Storage-Test');
  } catch (_error) {

    // in case of an error, like Safari's Private Mode, return false
    return false;
  }

  // we're good.
  return true;
}


if (typeof exports === 'object') {
  module.exports = hasLocalStorage;
}

},{}],25:[function(require,module,exports){
(function (global){
var exports = module.exports = {};
var localStorageMemory = require('localstorage-memory');
exports.hasLocalStorage = require('has-localstorage');

/**
 * returns localStorage-compatible API, either backed by window.localStorage
 * or memory if it's not available or not persistent.
 *
 * It also adds an object API (`.getObject(key)`,
 * `.setObject(key, properties)`) and a `isPresistent` property
 *
 * @returns {Object}
 */
exports.create = function () {
  var api;

  if (!exports.hasLocalStorage()) {
    api = localStorageMemory;
    api.isPersistent = false;
  } else {
    api = global.localStorage;
    api = {
      get length() { return global.localStorage.length; },
      getItem: global.localStorage.getItem.bind(global.localStorage),
      setItem: global.localStorage.setItem.bind(global.localStorage),
      removeItem: global.localStorage.removeItem.bind(global.localStorage),
      key: global.localStorage.key.bind(global.localStorage),
      clear: global.localStorage.clear.bind(global.localStorage),
    };

    api.isPersistent = true;
  }

  api.getObject = exports.getObject.bind(null, api);
  api.setObject = exports.setObject.bind(null, api);

  return api;
};

/**
 * sets key to passed Object.
 *
 * @returns undefined
 */
exports.setObject = function (store, key, object) {
  if (typeof object !== 'object') {
    return store.setItem(key, object);
  }

  return store.setItem(key, JSON.stringify(object));
};

/**
 * returns Object for key, or null
 *
 * @returns {Object|null}
 */
exports.getObject = function (store, key) {
  var item = store.getItem(key);

  if (!item) {
    return null;
  }

  try {
    return JSON.parse(item);
  } catch (e) {
    return item;
  }
};

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"has-localstorage":24,"localstorage-memory":46}],26:[function(require,module,exports){
var api = require('./api');
module.exports = api.create();

},{"./api":25}],27:[function(require,module,exports){
(function (global){
'use strict';
var Mutation = global.MutationObserver || global.WebKitMutationObserver;

var scheduleDrain;

{
  if (Mutation) {
    var called = 0;
    var observer = new Mutation(nextTick);
    var element = global.document.createTextNode('');
    observer.observe(element, {
      characterData: true
    });
    scheduleDrain = function () {
      element.data = (called = ++called % 2);
    };
  } else if (!global.setImmediate && typeof global.MessageChannel !== 'undefined') {
    var channel = new global.MessageChannel();
    channel.port1.onmessage = nextTick;
    scheduleDrain = function () {
      channel.port2.postMessage(0);
    };
  } else if ('document' in global && 'onreadystatechange' in global.document.createElement('script')) {
    scheduleDrain = function () {

      // Create a <script> element; its readystatechange event will be fired asynchronously once it is inserted
      // into the document. Do so, thus queuing up the task. Remember to clean up once it's been called.
      var scriptEl = global.document.createElement('script');
      scriptEl.onreadystatechange = function () {
        nextTick();

        scriptEl.onreadystatechange = null;
        scriptEl.parentNode.removeChild(scriptEl);
        scriptEl = null;
      };
      global.document.documentElement.appendChild(scriptEl);
    };
  } else {
    scheduleDrain = function () {
      setTimeout(nextTick, 0);
    };
  }
}

var draining;
var queue = [];
//named nextTick for less confusing stack traces
function nextTick() {
  draining = true;
  var i, oldQueue;
  var len = queue.length;
  while (len) {
    oldQueue = queue;
    queue = [];
    i = -1;
    while (++i < len) {
      oldQueue[i]();
    }
    len = queue.length;
  }
  draining = false;
}

module.exports = immediate;
function immediate(task) {
  if (queue.push(task) === 1 && !draining) {
    scheduleDrain();
  }
}

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{}],28:[function(require,module,exports){
if (typeof Object.create === 'function') {
  // implementation from standard node.js 'util' module
  module.exports = function inherits(ctor, superCtor) {
    ctor.super_ = superCtor
    ctor.prototype = Object.create(superCtor.prototype, {
      constructor: {
        value: ctor,
        enumerable: false,
        writable: true,
        configurable: true
      }
    });
  };
} else {
  // old school shim for old browsers
  module.exports = function inherits(ctor, superCtor) {
    ctor.super_ = superCtor
    var TempCtor = function () {}
    TempCtor.prototype = superCtor.prototype
    ctor.prototype = new TempCtor()
    ctor.prototype.constructor = ctor
  }
}

},{}],29:[function(require,module,exports){
module.exports = Array.isArray || function (arr) {
  return Object.prototype.toString.call(arr) == '[object Array]';
};

},{}],30:[function(require,module,exports){
var encodings = require('./lib/encodings');

module.exports = Codec;

function Codec(opts){
  this.opts = opts || {};
  this.encodings = encodings;
}

Codec.prototype._encoding = function(encoding){
  if (typeof encoding == 'string') encoding = encodings[encoding];
  if (!encoding) encoding = encodings.id;
  return encoding;
};

Codec.prototype._keyEncoding = function(opts, batchOpts){
  return this._encoding(batchOpts && batchOpts.keyEncoding
    || opts && opts.keyEncoding
    || this.opts.keyEncoding);
};

Codec.prototype._valueEncoding = function(opts, batchOpts){
  return this._encoding(
    batchOpts && (batchOpts.valueEncoding || batchOpts.encoding)
    || opts && (opts.valueEncoding || opts.encoding)
    || (this.opts.valueEncoding || this.opts.encoding));
};

Codec.prototype.encodeKey = function(key, opts, batchOpts){
  return this._keyEncoding(opts, batchOpts).encode(key);
};

Codec.prototype.encodeValue = function(value, opts, batchOpts){
  return this._valueEncoding(opts, batchOpts).encode(value);
};

Codec.prototype.decodeKey = function(key, opts){
  return this._keyEncoding(opts).decode(key);
};

Codec.prototype.decodeValue = function(value, opts){
  return this._valueEncoding(opts).decode(value);
};

Codec.prototype.encodeBatch = function(ops, opts){
  var self = this;

  return ops.map(function(_op){
    var op = {
      type: _op.type,
      key: self.encodeKey(_op.key, opts, _op)
    };
    if (self.keyAsBuffer(opts, _op)) op.keyEncoding = 'binary';
    if (_op.prefix) op.prefix = _op.prefix;
    if ('value' in _op) {
      op.value = self.encodeValue(_op.value, opts, _op);
      if (self.valueAsBuffer(opts, _op)) op.valueEncoding = 'binary';
    }
    return op;
  });
};

var ltgtKeys = ['lt', 'gt', 'lte', 'gte', 'start', 'end'];

Codec.prototype.encodeLtgt = function(ltgt){
  var self = this;
  var ret = {};
  Object.keys(ltgt).forEach(function(key){
    ret[key] = ltgtKeys.indexOf(key) > -1
      ? self.encodeKey(ltgt[key], ltgt)
      : ltgt[key]
  });
  return ret;
};

Codec.prototype.createStreamDecoder = function(opts){
  var self = this;

  if (opts.keys && opts.values) {
    return function(key, value){
      return {
        key: self.decodeKey(key, opts),
        value: self.decodeValue(value, opts)
      };
    };
  } else if (opts.keys) {
    return function(key) {
      return self.decodeKey(key, opts);
    }; 
  } else if (opts.values) {
    return function(_, value){
      return self.decodeValue(value, opts);
    }
  } else {
    return function(){};
  }
};

Codec.prototype.keyAsBuffer = function(opts){
  return this._keyEncoding(opts).buffer;
};

Codec.prototype.valueAsBuffer = function(opts){
  return this._valueEncoding(opts).buffer;
};


},{"./lib/encodings":31}],31:[function(require,module,exports){
(function (Buffer){

exports.utf8 = exports['utf-8'] = {
  encode: function(data){
    return isBinary(data)
      ? data
      : String(data);
  },
  decode: identity,
  buffer: false,
  type: 'utf8'
};

exports.json = {
  encode: JSON.stringify,
  decode: JSON.parse,
  buffer: false,
  type: 'json'
};

exports.binary = {
  encode: function(data){
    return isBinary(data)
      ? data
      : new Buffer(data);      
  },
  decode: identity,
  buffer: true,
  type: 'binary'
};

exports.id = {
  encode: function(data){
    return data;
  },
  decode: function(data){
    return data;
  },
  buffer: false,
  type: 'id'
};

var bufferEncodings = [
  'hex',
  'ascii',
  'base64',
  'ucs2',
  'ucs-2',
  'utf16le',
  'utf-16le'
];

bufferEncodings.forEach(function(type){
  exports[type] = {
    encode: function(data){
      return isBinary(data)
        ? data
        : new Buffer(data, type);
    },
    decode: function(buffer){
      return buffer.toString(type);
    },
    buffer: true,
    type: type
  };
});

function identity(value){
  return value;
}

function isBinary(data){
  return data === undefined
    || data === null
    || Buffer.isBuffer(data);
}


}).call(this,require("buffer").Buffer)
},{"buffer":105}],32:[function(require,module,exports){
/* Copyright (c) 2012-2015 LevelUP contributors
 * See list at <https://github.com/rvagg/node-levelup#contributing>
 * MIT License
 * <https://github.com/rvagg/node-levelup/blob/master/LICENSE.md>
 */

var createError   = require('errno').create
  , LevelUPError  = createError('LevelUPError')
  , NotFoundError = createError('NotFoundError', LevelUPError)

NotFoundError.prototype.notFound = true
NotFoundError.prototype.status   = 404

module.exports = {
    LevelUPError        : LevelUPError
  , InitializationError : createError('InitializationError', LevelUPError)
  , OpenError           : createError('OpenError', LevelUPError)
  , ReadError           : createError('ReadError', LevelUPError)
  , WriteError          : createError('WriteError', LevelUPError)
  , NotFoundError       : NotFoundError
  , EncodingError       : createError('EncodingError', LevelUPError)
}

},{"errno":20}],33:[function(require,module,exports){
var inherits = require('inherits');
var Readable = require('readable-stream').Readable;
var extend = require('xtend');
var EncodingError = require('level-errors').EncodingError;

module.exports = ReadStream;
inherits(ReadStream, Readable);

function ReadStream(iterator, options){
  if (!(this instanceof ReadStream)) return new ReadStream(iterator, options);
  Readable.call(this, extend(options, {
    objectMode: true
  }));
  this._iterator = iterator;
  this._destroyed = false;
  this._decoder = null;
  if (options && options.decoder) this._decoder = options.decoder;
  this.on('end', this._cleanup.bind(this));
}

ReadStream.prototype._read = function(){
  var self = this;
  if (this._destroyed) return;

  this._iterator.next(function(err, key, value){
    if (self._destroyed) return;
    if (err) return self.emit('error', err);
    if (key === undefined && value === undefined) {
      self.push(null);
    } else {
      if (!self._decoder) return self.push({ key: key, value: value });

      try {
        var value = self._decoder(key, value);
      } catch (err) {
        self.emit('error', new EncodingError(err));
        self.push(null);
        return;
      }
      self.push(value);
    }
  });
};

ReadStream.prototype.destroy =
ReadStream.prototype._cleanup = function(){
  var self = this;
  if (this._destroyed) return;
  this._destroyed = true;

  this._iterator.end(function(err){
    if (err) return self.emit('error', err);
    self.emit('close');
  });
};


},{"inherits":28,"level-errors":32,"readable-stream":77,"xtend":34}],34:[function(require,module,exports){
arguments[4][17][0].apply(exports,arguments)
},{"dup":17}],35:[function(require,module,exports){
/* Copyright (c) 2012-2016 LevelUP contributors
 * See list at <https://github.com/level/levelup#contributing>
 * MIT License
 * <https://github.com/level/levelup/blob/master/LICENSE.md>
 */

var util          = require('./util')
  , WriteError    = require('level-errors').WriteError

  , getOptions    = util.getOptions
  , dispatchError = util.dispatchError

function Batch (levelup, codec) {
  this._levelup = levelup
  this._codec = codec
  this.batch = levelup.db.batch()
  this.ops = []
  this.length = 0
}

Batch.prototype.put = function (key_, value_, options) {
  options = getOptions(options)

  var key   = this._codec.encodeKey(key_, options)
    , value = this._codec.encodeValue(value_, options)

  try {
    this.batch.put(key, value)
  } catch (e) {
    throw new WriteError(e)
  }
  this.ops.push({ type : 'put', key : key, value : value })
  this.length++

  return this
}

Batch.prototype.del = function (key_, options) {
  options = getOptions(options)

  var key = this._codec.encodeKey(key_, options)

  try {
    this.batch.del(key)
  } catch (err) {
    throw new WriteError(err)
  }
  this.ops.push({ type : 'del', key : key })
  this.length++

  return this
}

Batch.prototype.clear = function () {
  try {
    this.batch.clear()
  } catch (err) {
    throw new WriteError(err)
  }

  this.ops = []
  this.length = 0
  return this
}

Batch.prototype.write = function (callback) {
  var levelup = this._levelup
    , ops     = this.ops

  try {
    this.batch.write(function (err) {
      if (err)
        return dispatchError(levelup, new WriteError(err), callback)
      levelup.emit('batch', ops)
      if (callback)
        callback()
    })
  } catch (err) {
    throw new WriteError(err)
  }
}

module.exports = Batch

},{"./util":37,"level-errors":32}],36:[function(require,module,exports){
(function (process){
/* Copyright (c) 2012-2016 LevelUP contributors
 * See list at <https://github.com/level/levelup#contributing>
 * MIT License
 * <https://github.com/level/levelup/blob/master/LICENSE.md>
 */

var EventEmitter        = require('events').EventEmitter
  , inherits            = require('util').inherits
  , deprecate           = require('util').deprecate
  , extend              = require('xtend')
  , prr                 = require('prr')
  , DeferredLevelDOWN   = require('deferred-leveldown')
  , IteratorStream      = require('level-iterator-stream')

  , errors              = require('level-errors')
  , WriteError          = errors.WriteError
  , ReadError           = errors.ReadError
  , NotFoundError       = errors.NotFoundError
  , OpenError           = errors.OpenError
  , EncodingError       = errors.EncodingError
  , InitializationError = errors.InitializationError

  , util                = require('./util')
  , Batch               = require('./batch')
  , Codec               = require('level-codec')

  , getOptions          = util.getOptions
  , defaultOptions      = util.defaultOptions
  , getLevelDOWN        = util.getLevelDOWN
  , dispatchError       = util.dispatchError
  , isDefined           = util.isDefined

function getCallback (options, callback) {
  return typeof options == 'function' ? options : callback
}

// Possible LevelUP#_status values:
//  - 'new'     - newly created, not opened or closed
//  - 'opening' - waiting for the database to be opened, post open()
//  - 'open'    - successfully opened the database, available for use
//  - 'closing' - waiting for the database to be closed, post close()
//  - 'closed'  - database has been successfully closed, should not be
//                 used except for another open() operation

function LevelUP (location, options, callback) {
  if (!(this instanceof LevelUP))
    return new LevelUP(location, options, callback)

  var error

  EventEmitter.call(this)
  this.setMaxListeners(Infinity)

  if (typeof location == 'function') {
    options = typeof options == 'object' ? options : {}
    options.db = location
    location = null
  } else if (typeof location == 'object' && typeof location.db == 'function') {
    options = location
    location = null
  }


  if (typeof options == 'function') {
    callback = options
    options  = {}
  }

  if ((!options || typeof options.db != 'function') && typeof location != 'string') {
    error = new InitializationError(
        'Must provide a location for the database')
    if (callback) {
      return process.nextTick(function () {
        callback(error)
      })
    }
    throw error
  }

  options      = getOptions(options)
  this.options = extend(defaultOptions, options)
  this._codec = new Codec(this.options)
  this._status = 'new'
  // set this.location as enumerable but not configurable or writable
  prr(this, 'location', location, 'e')

  this.open(callback)
}

inherits(LevelUP, EventEmitter)

LevelUP.prototype.open = function (callback) {
  var self = this
    , dbFactory
    , db

  if (this.isOpen()) {
    if (callback)
      process.nextTick(function () { callback(null, self) })
    return this
  }

  if (this._isOpening()) {
    return callback && this.once(
        'open'
      , function () { callback(null, self) }
    )
  }

  this.emit('opening')

  this._status = 'opening'
  this.db      = new DeferredLevelDOWN(this.location)
  dbFactory    = this.options.db || getLevelDOWN()
  db           = dbFactory(this.location)

  db.open(this.options, function (err) {
    if (err) {
      return dispatchError(self, new OpenError(err), callback)
    } else {
      self.db.setDb(db)
      self.db = db
      self._status = 'open'
      if (callback)
        callback(null, self)
      self.emit('open')
      self.emit('ready')
    }
  })
}

LevelUP.prototype.close = function (callback) {
  var self = this

  if (this.isOpen()) {
    this._status = 'closing'
    this.db.close(function () {
      self._status = 'closed'
      self.emit('closed')
      if (callback)
        callback.apply(null, arguments)
    })
    this.emit('closing')
    this.db = new DeferredLevelDOWN(this.location)
  } else if (this._status == 'closed' && callback) {
    return process.nextTick(callback)
  } else if (this._status == 'closing' && callback) {
    this.once('closed', callback)
  } else if (this._isOpening()) {
    this.once('open', function () {
      self.close(callback)
    })
  }
}

LevelUP.prototype.isOpen = function () {
  return this._status == 'open'
}

LevelUP.prototype._isOpening = function () {
  return this._status == 'opening'
}

LevelUP.prototype.isClosed = function () {
  return (/^clos/).test(this._status)
}

function maybeError(db, options, callback) {
  if (!db._isOpening() && !db.isOpen()) {
    dispatchError(
        db
      , new ReadError('Database is not open')
      , callback
    )
    return true
  }
}

function writeError (db, message, callback) {
  dispatchError(
      db
     , new WriteError(message)
     , callback
  )
}

function readError (db, message, callback) {
  dispatchError(
      db
     , new ReadError(message)
     , callback
  )
}


LevelUP.prototype.get = function (key_, options, callback) {
  var self = this
    , key

  callback = getCallback(options, callback)

  if (maybeError(this, options, callback))
    return

  if (key_ === null || key_ === undefined || 'function' !== typeof callback)
    return readError(this
      , 'get() requires key and callback arguments', callback)

  options = util.getOptions(options)
  key = this._codec.encodeKey(key_, options)

  options.asBuffer = this._codec.valueAsBuffer(options)

  this.db.get(key, options, function (err, value) {
    if (err) {
      if ((/notfound/i).test(err) || err.notFound) {
        err = new NotFoundError(
            'Key not found in database [' + key_ + ']', err)
      } else {
        err = new ReadError(err)
      }
      return dispatchError(self, err, callback)
    }
    if (callback) {
      try {
        value = self._codec.decodeValue(value, options)
      } catch (e) {
        return callback(new EncodingError(e))
      }
      callback(null, value)
    }
  })
}

LevelUP.prototype.put = function (key_, value_, options, callback) {
  var self = this
    , key
    , value

  callback = getCallback(options, callback)

  if (key_ === null || key_ === undefined)
    return writeError(this, 'put() requires a key argument', callback)

  if (maybeError(this, options, callback))
    return

  options = getOptions(options)
  key     = this._codec.encodeKey(key_, options)
  value   = this._codec.encodeValue(value_, options)

  this.db.put(key, value, options, function (err) {
    if (err) {
      return dispatchError(self, new WriteError(err), callback)
    } else {
      self.emit('put', key_, value_)
      if (callback)
        callback()
    }
  })
}

LevelUP.prototype.del = function (key_, options, callback) {
  var self = this
    , key

  callback = getCallback(options, callback)

  if (key_ === null || key_ === undefined)
    return writeError(this, 'del() requires a key argument', callback)

  if (maybeError(this, options, callback))
    return

  options = getOptions(options)
  key     = this._codec.encodeKey(key_, options)

  this.db.del(key, options, function (err) {
    if (err) {
      return dispatchError(self, new WriteError(err), callback)
    } else {
      self.emit('del', key_)
      if (callback)
        callback()
    }
  })
}

LevelUP.prototype.batch = function (arr_, options, callback) {
  var self = this
    , keyEnc
    , valueEnc
    , arr

  if (!arguments.length)
    return new Batch(this, this._codec)

  callback = getCallback(options, callback)

  if (!Array.isArray(arr_))
    return writeError(this, 'batch() requires an array argument', callback)

  if (maybeError(this, options, callback))
    return

  options  = getOptions(options)
  arr      = self._codec.encodeBatch(arr_, options)
  arr      = arr.map(function (op) {
    if (!op.type && op.key !== undefined && op.value !== undefined)
      op.type = 'put'
    return op
  })

  this.db.batch(arr, options, function (err) {
    if (err) {
      return dispatchError(self, new WriteError(err), callback)
    } else {
      self.emit('batch', arr_)
      if (callback)
        callback()
    }
  })
}

LevelUP.prototype.approximateSize = deprecate(function (start_, end_, options, callback) {   
  var self = this    
    , start    
    , end    
   
  callback = getCallback(options, callback)    
   
  options = getOptions(options)    
   
  if (start_ === null || start_ === undefined    
        || end_ === null || end_ === undefined || 'function' !== typeof callback)    
    return readError(this, 'approximateSize() requires start, end and callback arguments', callback)   
   
  start = this._codec.encodeKey(start_, options)   
  end   = this._codec.encodeKey(end_, options)   
   
  this.db.approximateSize(start, end, function (err, size) {   
    if (err) {   
      return dispatchError(self, new OpenError(err), callback)   
    } else if (callback) {   
      callback(null, size)   
    }    
  })   
}, 'db.approximateSize() is deprecated. Use db.db.approximateSize() instead')

LevelUP.prototype.readStream =
LevelUP.prototype.createReadStream = function (options) {
  options = extend( {keys: true, values: true}, this.options, options)

  options.keyEncoding   = options.keyEncoding
  options.valueEncoding = options.valueEncoding

  options = this._codec.encodeLtgt(options);
  options.keyAsBuffer   = this._codec.keyAsBuffer(options)
  options.valueAsBuffer = this._codec.valueAsBuffer(options)

  if ('number' !== typeof options.limit)
    options.limit = -1

  return new IteratorStream(this.db.iterator(options), extend(options, {
    decoder: this._codec.createStreamDecoder(options)
  }))
}

LevelUP.prototype.keyStream =
LevelUP.prototype.createKeyStream = function (options) {
  return this.createReadStream(extend(options, { keys: true, values: false }))
}

LevelUP.prototype.valueStream =
LevelUP.prototype.createValueStream = function (options) {
  return this.createReadStream(extend(options, { keys: false, values: true }))
}

LevelUP.prototype.toString = function () {
  return 'LevelUP'
}

function utilStatic (name) {
  return function (location, callback) {
    getLevelDOWN()[name](location, callback || function () {})
  }
}

module.exports         = LevelUP
module.exports.errors  = require('level-errors')
module.exports.destroy = deprecate(
    utilStatic('destroy')
  , 'levelup.destroy() is deprecated. Use leveldown.destroy() instead'
)
module.exports.repair  = deprecate(
    utilStatic('repair')
  , 'levelup.repair() is deprecated. Use leveldown.repair() instead'
)


}).call(this,require('_process'))
},{"./batch":35,"./util":37,"_process":113,"deferred-leveldown":11,"events":107,"level-codec":30,"level-errors":32,"level-iterator-stream":33,"prr":71,"util":129,"xtend":38}],37:[function(require,module,exports){
/* Copyright (c) 2012-2016 LevelUP contributors
 * See list at <https://github.com/level/levelup#contributing>
 * MIT License
 * <https://github.com/level/levelup/blob/master/LICENSE.md>
 */

var extend         = require('xtend')
  , LevelUPError   = require('level-errors').LevelUPError
  , format         = require('util').format
  , defaultOptions = {
        createIfMissing : true
      , errorIfExists   : false
      , keyEncoding     : 'utf8'
      , valueEncoding   : 'utf8'
      , compression     : true
    }

  , leveldown

function getOptions (options) {
  if (typeof options == 'string')
    options = { valueEncoding: options }
  if (typeof options != 'object')
    options = {}
  return options
}

function getLevelDOWN () {
  if (leveldown)
    return leveldown

  var requiredVersion  = require('../package.json').devDependencies.leveldown
    , leveldownVersion

  try {
    leveldownVersion = require('leveldown/package').version
  } catch (e) {
    throw requireError(e)
  }

  if (!require('semver').satisfies(leveldownVersion, requiredVersion)) {
    throw new LevelUPError(
        'Installed version of LevelDOWN ('
      + leveldownVersion
      + ') does not match required version ('
      + requiredVersion
      + ')'
    )
  }

  try {
    return leveldown = require('leveldown')
  } catch (e) {
    throw requireError(e)
  }
}

function requireError (e) {
  var template = 'Failed to require LevelDOWN (%s). Try `npm install leveldown` if it\'s missing'
  return new LevelUPError(format(template, e.message))
}

function dispatchError (db, error, callback) {
  typeof callback == 'function' ? callback(error) : db.emit('error', error)
}

function isDefined (v) {
  return typeof v !== 'undefined'
}

module.exports = {
    defaultOptions  : defaultOptions
  , getOptions      : getOptions
  , getLevelDOWN    : getLevelDOWN
  , dispatchError   : dispatchError
  , isDefined       : isDefined
}

},{"../package.json":39,"level-errors":32,"leveldown":103,"leveldown/package":103,"semver":103,"util":129,"xtend":38}],38:[function(require,module,exports){
arguments[4][17][0].apply(exports,arguments)
},{"dup":17}],39:[function(require,module,exports){
module.exports={
  "_args": [
    [
      {
        "raw": "levelup@1.3.3",
        "scope": null,
        "escapedName": "levelup",
        "name": "levelup",
        "rawSpec": "1.3.3",
        "spec": "1.3.3",
        "type": "version"
      },
      "/opt/user/code/personal/github/leaflet.extras/inst/htmlwidgets/lib/TileLayer.PouchDBCached/node_modules/pouchdb-adapter-leveldb-core"
    ]
  ],
  "_from": "levelup@1.3.3",
  "_id": "levelup@1.3.3",
  "_inCache": true,
  "_location": "/levelup",
  "_nodeVersion": "4.4.7",
  "_npmOperationalInternal": {
    "host": "packages-12-west.internal.npmjs.com",
    "tmp": "tmp/levelup-1.3.3.tgz_1476029541340_0.44339725002646446"
  },
  "_npmUser": {
    "name": "juliangruber",
    "email": "julian@juliangruber.com"
  },
  "_npmVersion": "2.15.8",
  "_phantomChildren": {},
  "_requested": {
    "raw": "levelup@1.3.3",
    "scope": null,
    "escapedName": "levelup",
    "name": "levelup",
    "rawSpec": "1.3.3",
    "spec": "1.3.3",
    "type": "version"
  },
  "_requiredBy": [
    "/pouchdb-adapter-leveldb-core"
  ],
  "_resolved": "https://registry.npmjs.org/levelup/-/levelup-1.3.3.tgz",
  "_shasum": "bf9db62bdb6188d08eaaa2efcf6cc311916f41fd",
  "_shrinkwrap": null,
  "_spec": "levelup@1.3.3",
  "_where": "/opt/user/code/personal/github/leaflet.extras/inst/htmlwidgets/lib/TileLayer.PouchDBCached/node_modules/pouchdb-adapter-leveldb-core",
  "browser": {
    "leveldown": false,
    "leveldown/package": false,
    "semver": false
  },
  "bugs": {
    "url": "https://github.com/level/levelup/issues"
  },
  "contributors": [
    {
      "name": "Rod Vagg",
      "email": "r@va.gg",
      "url": "https://github.com/rvagg"
    },
    {
      "name": "John Chesley",
      "email": "john@chesl.es",
      "url": "https://github.com/chesles/"
    },
    {
      "name": "Jake Verbaten",
      "email": "raynos2@gmail.com",
      "url": "https://github.com/raynos"
    },
    {
      "name": "Dominic Tarr",
      "email": "dominic.tarr@gmail.com",
      "url": "https://github.com/dominictarr"
    },
    {
      "name": "Max Ogden",
      "email": "max@maxogden.com",
      "url": "https://github.com/maxogden"
    },
    {
      "name": "Lars-Magnus Skog",
      "email": "ralphtheninja@riseup.net",
      "url": "https://github.com/ralphtheninja"
    },
    {
      "name": "David Björklund",
      "email": "david.bjorklund@gmail.com",
      "url": "https://github.com/kesla"
    },
    {
      "name": "Julian Gruber",
      "email": "julian@juliangruber.com",
      "url": "https://github.com/juliangruber"
    },
    {
      "name": "Paolo Fragomeni",
      "email": "paolo@async.ly",
      "url": "https://github.com/0x00a"
    },
    {
      "name": "Anton Whalley",
      "email": "anton.whalley@nearform.com",
      "url": "https://github.com/No9"
    },
    {
      "name": "Matteo Collina",
      "email": "matteo.collina@gmail.com",
      "url": "https://github.com/mcollina"
    },
    {
      "name": "Pedro Teixeira",
      "email": "pedro.teixeira@gmail.com",
      "url": "https://github.com/pgte"
    },
    {
      "name": "James Halliday",
      "email": "mail@substack.net",
      "url": "https://github.com/substack"
    },
    {
      "name": "Jarrett Cruger",
      "email": "jcrugzz@gmail.com",
      "url": "https://github.com/jcrugzz"
    }
  ],
  "dependencies": {
    "deferred-leveldown": "~1.2.1",
    "level-codec": "~6.1.0",
    "level-errors": "~1.0.3",
    "level-iterator-stream": "~1.3.0",
    "prr": "~1.0.1",
    "semver": "~5.1.0",
    "xtend": "~4.0.0"
  },
  "description": "Fast & simple storage - a Node.js-style LevelDB wrapper",
  "devDependencies": {
    "async": "~1.5.0",
    "bustermove": "~1.0.0",
    "delayed": "~1.0.1",
    "faucet": "~0.0.1",
    "leveldown": "^1.1.0",
    "memdown": "~1.1.0",
    "msgpack-js": "~0.3.0",
    "referee": "~1.2.0",
    "rimraf": "~2.4.3",
    "slow-stream": "0.0.4",
    "tap": "~2.3.1",
    "tape": "~4.2.1"
  },
  "directories": {},
  "dist": {
    "shasum": "bf9db62bdb6188d08eaaa2efcf6cc311916f41fd",
    "tarball": "https://registry.npmjs.org/levelup/-/levelup-1.3.3.tgz"
  },
  "gitHead": "cced27dc9f0095823be5ed388ec601ec2bfe7366",
  "homepage": "https://github.com/level/levelup",
  "keywords": [
    "leveldb",
    "stream",
    "database",
    "db",
    "store",
    "storage",
    "json"
  ],
  "license": "MIT",
  "main": "lib/levelup.js",
  "maintainers": [
    {
      "name": "rvagg",
      "email": "rod@vagg.org"
    },
    {
      "name": "ralphtheninja",
      "email": "ralphtheninja@riseup.net"
    },
    {
      "name": "juliangruber",
      "email": "julian@juliangruber.com"
    }
  ],
  "name": "levelup",
  "optionalDependencies": {},
  "readme": "ERROR: No README data found!",
  "repository": {
    "type": "git",
    "url": "git+https://github.com/level/levelup.git"
  },
  "scripts": {
    "test": "tape test/*-test.js | faucet"
  },
  "version": "1.3.3"
}

},{}],40:[function(require,module,exports){
'use strict';
var immediate = require('immediate');

/* istanbul ignore next */
function INTERNAL() {}

var handlers = {};

var REJECTED = ['REJECTED'];
var FULFILLED = ['FULFILLED'];
var PENDING = ['PENDING'];

module.exports = Promise;

function Promise(resolver) {
  if (typeof resolver !== 'function') {
    throw new TypeError('resolver must be a function');
  }
  this.state = PENDING;
  this.queue = [];
  this.outcome = void 0;
  if (resolver !== INTERNAL) {
    safelyResolveThenable(this, resolver);
  }
}

Promise.prototype["catch"] = function (onRejected) {
  return this.then(null, onRejected);
};
Promise.prototype.then = function (onFulfilled, onRejected) {
  if (typeof onFulfilled !== 'function' && this.state === FULFILLED ||
    typeof onRejected !== 'function' && this.state === REJECTED) {
    return this;
  }
  var promise = new this.constructor(INTERNAL);
  if (this.state !== PENDING) {
    var resolver = this.state === FULFILLED ? onFulfilled : onRejected;
    unwrap(promise, resolver, this.outcome);
  } else {
    this.queue.push(new QueueItem(promise, onFulfilled, onRejected));
  }

  return promise;
};
function QueueItem(promise, onFulfilled, onRejected) {
  this.promise = promise;
  if (typeof onFulfilled === 'function') {
    this.onFulfilled = onFulfilled;
    this.callFulfilled = this.otherCallFulfilled;
  }
  if (typeof onRejected === 'function') {
    this.onRejected = onRejected;
    this.callRejected = this.otherCallRejected;
  }
}
QueueItem.prototype.callFulfilled = function (value) {
  handlers.resolve(this.promise, value);
};
QueueItem.prototype.otherCallFulfilled = function (value) {
  unwrap(this.promise, this.onFulfilled, value);
};
QueueItem.prototype.callRejected = function (value) {
  handlers.reject(this.promise, value);
};
QueueItem.prototype.otherCallRejected = function (value) {
  unwrap(this.promise, this.onRejected, value);
};

function unwrap(promise, func, value) {
  immediate(function () {
    var returnValue;
    try {
      returnValue = func(value);
    } catch (e) {
      return handlers.reject(promise, e);
    }
    if (returnValue === promise) {
      handlers.reject(promise, new TypeError('Cannot resolve promise with itself'));
    } else {
      handlers.resolve(promise, returnValue);
    }
  });
}

handlers.resolve = function (self, value) {
  var result = tryCatch(getThen, value);
  if (result.status === 'error') {
    return handlers.reject(self, result.value);
  }
  var thenable = result.value;

  if (thenable) {
    safelyResolveThenable(self, thenable);
  } else {
    self.state = FULFILLED;
    self.outcome = value;
    var i = -1;
    var len = self.queue.length;
    while (++i < len) {
      self.queue[i].callFulfilled(value);
    }
  }
  return self;
};
handlers.reject = function (self, error) {
  self.state = REJECTED;
  self.outcome = error;
  var i = -1;
  var len = self.queue.length;
  while (++i < len) {
    self.queue[i].callRejected(error);
  }
  return self;
};

function getThen(obj) {
  // Make sure we only access the accessor once as required by the spec
  var then = obj && obj.then;
  if (obj && typeof obj === 'object' && typeof then === 'function') {
    return function appyThen() {
      then.apply(obj, arguments);
    };
  }
}

function safelyResolveThenable(self, thenable) {
  // Either fulfill, reject or reject with error
  var called = false;
  function onError(value) {
    if (called) {
      return;
    }
    called = true;
    handlers.reject(self, value);
  }

  function onSuccess(value) {
    if (called) {
      return;
    }
    called = true;
    handlers.resolve(self, value);
  }

  function tryToUnwrap() {
    thenable(onSuccess, onError);
  }

  var result = tryCatch(tryToUnwrap);
  if (result.status === 'error') {
    onError(result.value);
  }
}

function tryCatch(func, value) {
  var out = {};
  try {
    out.value = func(value);
    out.status = 'success';
  } catch (e) {
    out.status = 'error';
    out.value = e;
  }
  return out;
}

Promise.resolve = resolve;
function resolve(value) {
  if (value instanceof this) {
    return value;
  }
  return handlers.resolve(new this(INTERNAL), value);
}

Promise.reject = reject;
function reject(reason) {
  var promise = new this(INTERNAL);
  return handlers.reject(promise, reason);
}

Promise.all = all;
function all(iterable) {
  var self = this;
  if (Object.prototype.toString.call(iterable) !== '[object Array]') {
    return this.reject(new TypeError('must be an array'));
  }

  var len = iterable.length;
  var called = false;
  if (!len) {
    return this.resolve([]);
  }

  var values = new Array(len);
  var resolved = 0;
  var i = -1;
  var promise = new this(INTERNAL);

  while (++i < len) {
    allResolver(iterable[i], i);
  }
  return promise;
  function allResolver(value, i) {
    self.resolve(value).then(resolveFromAll, function (error) {
      if (!called) {
        called = true;
        handlers.reject(promise, error);
      }
    });
    function resolveFromAll(outValue) {
      values[i] = outValue;
      if (++resolved === len && !called) {
        called = true;
        handlers.resolve(promise, values);
      }
    }
  }
}

Promise.race = race;
function race(iterable) {
  var self = this;
  if (Object.prototype.toString.call(iterable) !== '[object Array]') {
    return this.reject(new TypeError('must be an array'));
  }

  var len = iterable.length;
  var called = false;
  if (!len) {
    return this.resolve([]);
  }

  var i = -1;
  var promise = new this(INTERNAL);

  while (++i < len) {
    resolver(iterable[i]);
  }
  return promise;
  function resolver(value) {
    self.resolve(value).then(function (response) {
      if (!called) {
        called = true;
        handlers.resolve(promise, response);
      }
    }, function (error) {
      if (!called) {
        called = true;
        handlers.reject(promise, error);
      }
    });
  }
}

},{"immediate":27}],41:[function(require,module,exports){
(function (process,global,Buffer){
'use strict';

var inherits = require('inherits');
var AbstractLevelDOWN = require('abstract-leveldown').AbstractLevelDOWN;
var AbstractIterator = require('abstract-leveldown').AbstractIterator;

var LocalStorage = require('./localstorage').LocalStorage;
var LocalStorageCore = require('./localstorage-core');
var utils = require('./utils');

// see http://stackoverflow.com/a/15349865/680742
var nextTick = global.setImmediate || process.nextTick;

function LDIterator(db, options) {

  AbstractIterator.call(this, db);

  this._reverse = !!options.reverse;
  this._endkey     = options.end;
  this._startkey   = options.start;
  this._gt      = options.gt;
  this._gte     = options.gte;
  this._lt      = options.lt;
  this._lte     = options.lte;
  this._exclusiveStart = options.exclusiveStart;
  this._limit = options.limit;
  this._count = 0;

  this.onInitCompleteListeners = [];
}

inherits(LDIterator, AbstractIterator);

LDIterator.prototype._init = function (callback) {
  nextTick(function () {
    callback();
  });
};

LDIterator.prototype._next = function (callback) {
  var self = this;

  function onInitComplete() {
    if (self._pos === self._keys.length || self._pos < 0) { // done reading
      return callback();
    }

    var key = self._keys[self._pos];

    if (!!self._endkey && (self._reverse ? key < self._endkey : key > self._endkey)) {
      return callback();
    }

    if (!!self._limit && self._limit > 0 && self._count++ >= self._limit) {
      return callback();
    }

    if ((self._lt  && key >= self._lt) ||
      (self._lte && key > self._lte) ||
      (self._gt  && key <= self._gt) ||
      (self._gte && key < self._gte)) {
      return callback();
    }

    self._pos += self._reverse ? -1 : 1;
    self.db.container.getItem(key, function (err, value) {
      if (err) {
        if (err.message === 'NotFound') {
          return nextTick(function () {
            self._next(callback);
          });
        }
        return callback(err);
      }
      callback(null, key, value);
    });
  }
  if (!self.initStarted) {
    process.nextTick(function () {
      self.initStarted = true;
      self._init(function (err) {
        if (err) {
          return callback(err);
        }
        self.db.container.keys(function (err, keys) {
          if (err) {
            return callback(err);
          }
          self._keys = keys;
          if (self._startkey) {
            var index = utils.sortedIndexOf(self._keys, self._startkey);
            var startkey = (index >= self._keys.length || index < 0) ?
              undefined : self._keys[index];
            self._pos = index;
            if (self._reverse) {
              if (self._exclusiveStart || startkey !== self._startkey) {
                self._pos--;
              }
            } else if (self._exclusiveStart && startkey === self._startkey) {
              self._pos++;
            }
          } else {
            self._pos = self._reverse ? self._keys.length - 1 : 0;
          }
          onInitComplete();

          self.initCompleted = true;
          var i = -1;
          while (++i < self.onInitCompleteListeners.length) {
            nextTick(self.onInitCompleteListeners[i]);
          }
        });
      });
    });
  } else if (!self.initCompleted) {
    self.onInitCompleteListeners.push(onInitComplete);
  } else {
    process.nextTick(onInitComplete);
  }
};

function LD(location) {
  if (!(this instanceof LD)) {
    return new LD(location);
  }
  AbstractLevelDOWN.call(this, location);
  this.container = new LocalStorage(location);
}

inherits(LD, AbstractLevelDOWN);

LD.prototype._open = function (options, callback) {
  this.container.init(callback);
};

LD.prototype._put = function (key, value, options, callback) {

  var err = checkKeyValue(key, 'key');

  if (err) {
    return nextTick(function () {
      callback(err);
    });
  }

  err = checkKeyValue(value, 'value');

  if (err) {
    return nextTick(function () {
      callback(err);
    });
  }

  if (typeof value === 'object' && !Buffer.isBuffer(value) && value.buffer === undefined) {
    var obj = {};
    obj.storetype = "json";
    obj.data = value;
    value = JSON.stringify(obj);
  }

  this.container.setItem(key, value, callback);
};

LD.prototype._get = function (key, options, callback) {

  var err = checkKeyValue(key, 'key');

  if (err) {
    return nextTick(function () {
      callback(err);
    });
  }

  if (!Buffer.isBuffer(key)) {
    key = String(key);
  }
  this.container.getItem(key, function (err, value) {

    if (err) {
      return callback(err);
    }

    if (options.asBuffer !== false && !Buffer.isBuffer(value)) {
      value = new Buffer(value);
    }


    if (options.asBuffer === false) {
      if (value.indexOf("{\"storetype\":\"json\",\"data\"") > -1) {
        var res = JSON.parse(value);
        value = res.data;
      }
    }
    callback(null, value);
  });
};

LD.prototype._del = function (key, options, callback) {

  var err = checkKeyValue(key, 'key');

  if (err) {
    return nextTick(function () {
      callback(err);
    });
  }
  if (!Buffer.isBuffer(key)) {
    key = String(key);
  }

  this.container.removeItem(key, callback);
};

LD.prototype._batch = function (array, options, callback) {
  var self = this;
  nextTick(function () {
    var err;
    var key;
    var value;

    var numDone = 0;
    var overallErr;
    function checkDone() {
      if (++numDone === array.length) {
        callback(overallErr);
      }
    }

    if (Array.isArray(array) && array.length) {
      for (var i = 0; i < array.length; i++) {
        var task = array[i];
        if (task) {
          key = Buffer.isBuffer(task.key) ? task.key : String(task.key);
          err = checkKeyValue(key, 'key');
          if (err) {
            overallErr = err;
            checkDone();
          } else if (task.type === 'del') {
            self._del(task.key, options, checkDone);
          } else if (task.type === 'put') {
            value = Buffer.isBuffer(task.value) ? task.value : String(task.value);
            err = checkKeyValue(value, 'value');
            if (err) {
              overallErr = err;
              checkDone();
            } else {
              self._put(key, value, options, checkDone);
            }
          }
        } else {
          checkDone();
        }
      }
    } else {
      callback();
    }
  });
};

LD.prototype._iterator = function (options) {
  return new LDIterator(this, options);
};

LD.destroy = function (name, callback) {
  LocalStorageCore.destroy(name, callback);
};

function checkKeyValue(obj, type) {
  if (obj === null || obj === undefined) {
    return new Error(type + ' cannot be `null` or `undefined`');
  }
  if (obj === null || obj === undefined) {
    return new Error(type + ' cannot be `null` or `undefined`');
  }

  if (type === 'key') {

    if (obj instanceof Boolean) {
      return new Error(type + ' cannot be `null` or `undefined`');
    }
    if (obj === '') {
      return new Error(type + ' cannot be empty');
    }
  }
  if (obj.toString().indexOf("[object ArrayBuffer]") === 0) {
    if (obj.byteLength === 0 || obj.byteLength === undefined) {
      return new Error(type + ' cannot be an empty Buffer');
    }
  }

  if (Buffer.isBuffer(obj)) {
    if (obj.length === 0) {
      return new Error(type + ' cannot be an empty Buffer');
    }
  } else if (String(obj) === '') {
    return new Error(type + ' cannot be an empty String');
  }
}

module.exports = LD;

}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {},require("buffer").Buffer)
},{"./localstorage":43,"./localstorage-core":42,"./utils":45,"_process":113,"abstract-leveldown":4,"buffer":105,"inherits":28}],42:[function(require,module,exports){
(function (process,global){
'use strict';

//
// Class that should contain everything necessary to interact
// with localStorage as a generic key-value store.
// The idea is that authors who want to create an AbstractKeyValueDOWN
// module (e.g. on lawnchair, S3, whatever) will only have to
// reimplement this file.
//

// see http://stackoverflow.com/a/15349865/680742
var nextTick = global.setImmediate || process.nextTick;

// We use humble-localstorage as a wrapper for localStorage because
// it falls back to an in-memory implementation in environments without
// localStorage, like Node or Safari private browsing.
var storage = require('humble-localstorage');

function callbackify(callback, fun) {
  var val;
  var err;
  try {
    val = fun();
  } catch (e) {
    err = e;
  }
  nextTick(function () {
    callback(err, val);
  });
}

function createPrefix(dbname) {
  return dbname.replace(/!/g, '!!') + '!'; // escape bangs in dbname;
}

function LocalStorageCore(dbname) {
  this._prefix = createPrefix(dbname);
}

LocalStorageCore.prototype.getKeys = function (callback) {
  var self = this;
  callbackify(callback, function () {
    var keys = [];
    var prefixLen = self._prefix.length;
    var i = -1;
    var len = storage.length;
    while (++i < len) {
      var fullKey = storage.key(i);
      if (fullKey.substring(0, prefixLen) === self._prefix) {
        keys.push(fullKey.substring(prefixLen));
      }
    }
    keys.sort();
    return keys;
  });
};

LocalStorageCore.prototype.put = function (key, value, callback) {
  var self = this;
  callbackify(callback, function () {
    storage.setItem(self._prefix + key, value);
  });
};

LocalStorageCore.prototype.get = function (key, callback) {
  var self = this;
  callbackify(callback, function () {
    return storage.getItem(self._prefix + key);
  });
};

LocalStorageCore.prototype.remove = function (key, callback) {
  var self = this;
  callbackify(callback, function () {
    storage.removeItem(self._prefix + key);
  });
};

LocalStorageCore.destroy = function (dbname, callback) {
  var prefix = createPrefix(dbname);
  callbackify(callback, function () {
    var keysToDelete = [];
    var i = -1;
    var len = storage.length;
    while (++i < len) {
      var key = storage.key(i);
      if (key.substring(0, prefix.length) === prefix) {
        keysToDelete.push(key);
      }
    }
    keysToDelete.forEach(function (key) {
      storage.removeItem(key);
    });
  });
};

module.exports = LocalStorageCore;
}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"_process":113,"humble-localstorage":26}],43:[function(require,module,exports){
(function (Buffer){
'use strict';

// ArrayBuffer/Uint8Array are old formats that date back to before we
// had a proper browserified buffer type. they may be removed later
var arrayBuffPrefix = 'ArrayBuffer:';
var arrayBuffRegex = new RegExp('^' + arrayBuffPrefix);
var uintPrefix = 'Uint8Array:';
var uintRegex = new RegExp('^' + uintPrefix);

// this is the new encoding format used going forward
var bufferPrefix = 'Buff:';
var bufferRegex = new RegExp('^' + bufferPrefix);

var utils = require('./utils');
var LocalStorageCore = require('./localstorage-core');
var TaskQueue = require('./taskqueue');
var d64 = require('d64');

function LocalStorage(dbname) {
  this._store = new LocalStorageCore(dbname);
  this._queue = new TaskQueue();
}

LocalStorage.prototype.sequentialize = function (callback, fun) {
  this._queue.add(fun, callback);
};

LocalStorage.prototype.init = function (callback) {
  var self = this;
  self.sequentialize(callback, function (callback) {
    self._store.getKeys(function (err, keys) {
      if (err) {
        return callback(err);
      }
      self._keys = keys;
      return callback();
    });
  });
};

LocalStorage.prototype.keys = function (callback) {
  var self = this;
  self.sequentialize(callback, function (callback) {
    callback(null, self._keys.slice());
  });
};

//setItem: Saves and item at the key provided.
LocalStorage.prototype.setItem = function (key, value, callback) {
  var self = this;
  self.sequentialize(callback, function (callback) {
    if (Buffer.isBuffer(value)) {
      value = bufferPrefix + d64.encode(value);
    }

    var idx = utils.sortedIndexOf(self._keys, key);
    if (self._keys[idx] !== key) {
      self._keys.splice(idx, 0, key);
    }
    self._store.put(key, value, callback);
  });
};

//getItem: Returns the item identified by it's key.
LocalStorage.prototype.getItem = function (key, callback) {
  var self = this;
  self.sequentialize(callback, function (callback) {
    self._store.get(key, function (err, retval) {
      if (err) {
        return callback(err);
      }
      if (typeof retval === 'undefined' || retval === null) {
        // 'NotFound' error, consistent with LevelDOWN API
        return callback(new Error('NotFound'));
      }
      if (typeof retval !== 'undefined') {
        if (bufferRegex.test(retval)) {
          retval = d64.decode(retval.substring(bufferPrefix.length));
        } else if (arrayBuffRegex.test(retval)) {
          // this type is kept for backwards
          // compatibility with older databases, but may be removed
          // after a major version bump
          retval = retval.substring(arrayBuffPrefix.length);
          retval = new ArrayBuffer(atob(retval).split('').map(function (c) {
            return c.charCodeAt(0);
          }));
        } else if (uintRegex.test(retval)) {
          // ditto
          retval = retval.substring(uintPrefix.length);
          retval = new Uint8Array(atob(retval).split('').map(function (c) {
            return c.charCodeAt(0);
          }));
        }
      }
      callback(null, retval);
    });
  });
};

//removeItem: Removes the item identified by it's key.
LocalStorage.prototype.removeItem = function (key, callback) {
  var self = this;
  self.sequentialize(callback, function (callback) {
    var idx = utils.sortedIndexOf(self._keys, key);
    if (self._keys[idx] === key) {
      self._keys.splice(idx, 1);
      self._store.remove(key, function (err) {
        if (err) {
          return callback(err);
        }
        callback();
      });
    } else {
      callback();
    }
  });
};

LocalStorage.prototype.length = function (callback) {
  var self = this;
  self.sequentialize(callback, function (callback) {
    callback(null, self._keys.length);
  });
};

exports.LocalStorage = LocalStorage;

}).call(this,{"isBuffer":require("../../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js")})
},{"../../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js":110,"./localstorage-core":42,"./taskqueue":44,"./utils":45,"d64":7}],44:[function(require,module,exports){
(function (process,global){
'use strict';

var argsarray = require('argsarray');
var Queue = require('tiny-queue');

// see http://stackoverflow.com/a/15349865/680742
var nextTick = global.setImmediate || process.nextTick;

function TaskQueue() {
  this.queue = new Queue();
  this.running = false;
}

TaskQueue.prototype.add = function (fun, callback) {
  this.queue.push({fun: fun, callback: callback});
  this.processNext();
};

TaskQueue.prototype.processNext = function () {
  var self = this;
  if (self.running || !self.queue.length) {
    return;
  }
  self.running = true;

  var task = self.queue.shift();
  nextTick(function () {
    task.fun(argsarray(function (args) {
      task.callback.apply(null, args);
      self.running = false;
      self.processNext();
    }));
  });
};

module.exports = TaskQueue;

}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"_process":113,"argsarray":5,"tiny-queue":98}],45:[function(require,module,exports){
'use strict';
// taken from rvagg/memdown commit 2078b40
exports.sortedIndexOf = function(arr, item) {
  var low = 0;
  var high = arr.length;
  var mid;
  while (low < high) {
    mid = (low + high) >>> 1;
    if (arr[mid] < item) {
      low = mid + 1;
    } else {
      high = mid;
    }
  }
  return low;
};

},{}],46:[function(require,module,exports){
(function(root) {
  var localStorageMemory = {};
  var cache = {};

  /**
   * number of stored items.
   */
  localStorageMemory.length = 0;

  /**
   * returns item for passed key, or null
   *
   * @para {String} key
   *       name of item to be returned
   * @returns {String|null}
   */
  localStorageMemory.getItem = function(key) {
    return cache[key] || null;
  };

  /**
   * sets item for key to passed value, as String
   *
   * @para {String} key
   *       name of item to be set
   * @para {String} value
   *       value, will always be turned into a String
   * @returns {undefined}
   */
  localStorageMemory.setItem = function(key, value) {
    if (typeof value === 'undefined') {
      localStorageMemory.removeItem(key);
    } else {
      if (!(cache.hasOwnProperty(key))) {
        localStorageMemory.length++;
      }

      cache[key] = '' + value;
    }
  };

  /**
   * removes item for passed key
   *
   * @para {String} key
   *       name of item to be removed
   * @returns {undefined}
   */
  localStorageMemory.removeItem = function(key) {
    if (cache.hasOwnProperty(key)) {
      delete cache[key];
      localStorageMemory.length--;
    }
  };

  /**
   * returns name of key at passed index
   *
   * @para {Number} index
   *       Position for key to be returned (starts at 0)
   * @returns {String|null}
   */
  localStorageMemory.key = function(index) {
    return Object.keys(cache)[index] || null;
  };

  /**
   * removes all stored items and sets length to 0
   *
   * @returns {undefined}
   */
  localStorageMemory.clear = function() {
    cache = {};
    localStorageMemory.length = 0;
  };

  if (typeof exports === 'object') {
    module.exports = localStorageMemory;
  } else {
    root.localStorageMemory = localStorageMemory;
  }
})(this);

},{}],47:[function(require,module,exports){
(function (Buffer){

exports.compare = function (a, b) {

  if(Buffer.isBuffer(a)) {
    var l = Math.min(a.length, b.length)
    for(var i = 0; i < l; i++) {
      var cmp = a[i] - b[i]
      if(cmp) return cmp
    }
    return a.length - b.length
  }

  return a < b ? -1 : a > b ? 1 : 0
}

function has(obj, key) {
  return Object.hasOwnProperty.call(obj, key)
}

// to be compatible with the current abstract-leveldown tests
// nullish or empty strings.
// I could use !!val but I want to permit numbers and booleans,
// if possible.

function isDef (val) {
  return val !== undefined && val !== ''
}

function has (range, name) {
  return Object.hasOwnProperty.call(range, name)
}

function hasKey(range, name) {
  return Object.hasOwnProperty.call(range, name) && name
}

var lowerBoundKey = exports.lowerBoundKey = function (range) {
    return (
       hasKey(range, 'gt')
    || hasKey(range, 'gte')
    || hasKey(range, 'min')
    || (range.reverse ? hasKey(range, 'end') : hasKey(range, 'start'))
    || undefined
    )
}

var lowerBound = exports.lowerBound = function (range) {
  var k = lowerBoundKey(range)
  return k && range[k]
}

exports.lowerBoundInclusive = function (range) {
  return has(range, 'gt') ? false : true
}

exports.upperBoundInclusive =
  function (range) {
    return has(range, 'lt') || !range.minEx ? false : true
  }

var lowerBoundExclusive = exports.lowerBoundExclusive =
  function (range) {
    return has(range, 'gt') || range.minEx ? true : false
  }

var upperBoundExclusive = exports.upperBoundExclusive =
  function (range) {
    return has(range, 'lt') ? true : false
  }

var upperBoundKey = exports.upperBoundKey = function (range) {
    return (
       hasKey(range, 'lt')
    || hasKey(range, 'lte')
    || hasKey(range, 'max')
    || (range.reverse ? hasKey(range, 'start') : hasKey(range, 'end'))
    || undefined
    )
}

var upperBound = exports.upperBound = function (range) {
  var k = upperBoundKey(range)
  return k && range[k]
}

function id (e) { return e }

exports.toLtgt = function (range, _range, map, lower, upper) {
  _range = _range || {}
  map = map || id
  var defaults = arguments.length > 3
  var lb = exports.lowerBoundKey(range)
  var ub = exports.upperBoundKey(range)
  if(lb) {
    if(lb === 'gt') _range.gt = map(range.gt, false)
    else            _range.gte = map(range[lb], false)
  }
  else if(defaults)
    _range.gte = map(lower, false)

  if(ub) {
    if(ub === 'lt') _range.lt = map(range.lt, true)
    else            _range.lte = map(range[ub], true)
  }
  else if(defaults)
    _range.lte = map(upper, true)

  if(range.reverse != null)
    _range.reverse = !!range.reverse

  //if range was used mutably
  //(in level-sublevel it's part of an options object
  //that has more properties on it.)
  if(has(_range, 'max'))   delete _range.max
  if(has(_range, 'min'))   delete _range.min
  if(has(_range, 'start')) delete _range.start
  if(has(_range, 'end'))   delete _range.end

  return _range
}

exports.contains = function (range, key, compare) {
  compare = compare || exports.compare

  var lb = lowerBound(range)
  if(isDef(lb)) {
    var cmp = compare(key, lb)
    if(cmp < 0 || (cmp === 0 && lowerBoundExclusive(range)))
      return false
  }

  var ub = upperBound(range)
  if(isDef(ub)) {
    var cmp = compare(key, ub)
    if(cmp > 0 || (cmp === 0) && upperBoundExclusive(range))
      return false
  }

  return true
}

exports.filter = function (range, compare) {
  return function (key) {
    return exports.contains(range, key, compare)
  }
}

}).call(this,{"isBuffer":require("../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js")})
},{"../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js":110}],48:[function(require,module,exports){
(function (process,global,Buffer){
var inherits          = require('inherits')
  , AbstractLevelDOWN = require('abstract-leveldown').AbstractLevelDOWN
  , AbstractIterator  = require('abstract-leveldown').AbstractIterator
  , ltgt              = require('ltgt')
  , createRBT = require('functional-red-black-tree')
  , globalStore       = {}
/* istanbul ignore next */
var setImmediate = global.setImmediate || process.nextTick

function gt(value) {
  return ltgt.compare(value, this._end) > 0
}

function gte(value) {
  return ltgt.compare(value, this._end) >= 0
}

function lt(value) {
  return ltgt.compare(value, this._end) < 0
}

function lte(value) {
  return ltgt.compare(value, this._end) <= 0
}


function MemIterator (db, options) {
  AbstractIterator.call(this, db)
  this._limit   = options.limit

  if (this._limit === -1)
    this._limit = Infinity

  var tree = db._store[db._location]

  this.keyAsBuffer = options.keyAsBuffer !== false
  this.valueAsBuffer = options.valueAsBuffer !== false
  this._reverse   = options.reverse
  this._options = options
  this._done = 0

  if (!this._reverse) {
    this._incr = 'next'
    this._start = ltgt.lowerBound(options)
    this._end = ltgt.upperBound(options)

    if (typeof this._start === 'undefined')
      this._tree = tree.begin
    else if (ltgt.lowerBoundInclusive(options))
      this._tree = tree.ge(this._start)
    else
      this._tree = tree.gt(this._start)

    if (this._end) {
      if (ltgt.upperBoundInclusive(options))
        this._test = lte
      else
        this._test = lt
    }

  } else {
    this._incr = 'prev'
    this._start = ltgt.upperBound(options)
    this._end = ltgt.lowerBound(options)

    if (typeof this._start === 'undefined')
      this._tree = tree.end
    else if (ltgt.upperBoundInclusive(options))
      this._tree = tree.le(this._start)
    else
      this._tree = tree.lt(this._start)

    if (this._end) {
      if (ltgt.lowerBoundInclusive(options))
        this._test = gte
      else
        this._test = gt
    }

  }

}

inherits(MemIterator, AbstractIterator)

MemIterator.prototype._next = function (callback) {
  var key
    , value

  if (this._done++ >= this._limit)
    return setImmediate(callback)

  if (!this._tree.valid)
    return setImmediate(callback)

  key = this._tree.key
  value = this._tree.value

  if (!this._test(key))
    return setImmediate(callback)

  if (this.keyAsBuffer)
    key = new Buffer(key)

  if (this.valueAsBuffer)
    value = new Buffer(value)

  this._tree[this._incr]()

  setImmediate(function callNext() {
    callback(null, key, value)
  })
}

MemIterator.prototype._test = function () {return true}

function MemDOWN (location) {
  if (!(this instanceof MemDOWN))
    return new MemDOWN(location)

  AbstractLevelDOWN.call(this, typeof location == 'string' ? location : '')

  this._location = this.location ? ('$' + this.location) : '_tree'
  this._store = this.location ? globalStore: this
  this._store[this._location] = this._store[this._location] || createRBT(ltgt.compare)
}

MemDOWN.clearGlobalStore = function (strict) {
  if (strict) {
    Object.keys(globalStore).forEach(function (key) {
      delete globalStore[key]
    })
  } else {
    globalStore = {}
  }
}

inherits(MemDOWN, AbstractLevelDOWN)

MemDOWN.prototype._open = function (options, callback) {
  var self = this
  setImmediate(function callNext() { callback(null, self) })
}

MemDOWN.prototype._put = function (key, value, options, callback) {
  if (typeof value === 'undefined' || value === null) value = ''

  var iter = this._store[this._location].find(key)

  if (iter.valid) {
    this._store[this._location] = iter.update(value)
  } else {
    this._store[this._location] = this._store[this._location].insert(key, value)
  }

  setImmediate(callback)
}

MemDOWN.prototype._get = function (key, options, callback) {
  var value = this._store[this._location].get(key)

  if (typeof value === 'undefined') {
    // 'NotFound' error, consistent with LevelDOWN API
    return setImmediate(function callNext() { callback(new Error('NotFound')) })
  }

  if (options.asBuffer !== false && !this._isBuffer(value))
    value = new Buffer(String(value))

  setImmediate(function callNext () {
    callback(null, value)
  })

}

MemDOWN.prototype._del = function (key, options, callback) {
  this._store[this._location] = this._store[this._location].remove(key)
  setImmediate(callback)
}

MemDOWN.prototype._batch = function (array, options, callback) {
  var i = -1
    , key
    , value
    , iter
    , len = array.length
    , tree = this._store[this._location]

  while (++i < len) {
    if (!array[i])
      continue

    key = this._isBuffer(array[i].key) ? array[i].key : String(array[i].key)
    iter = tree.find(key)

    if (array[i].type === 'put') {
      value = this._isBuffer(array[i].value) ? array[i].value : String(array[i].value)
      tree = iter.valid ? iter.update(value) : tree.insert(key, value)
    } else {
      tree = iter.remove()
    }
  }

  this._store[this._location] = tree

  setImmediate(callback)
}

MemDOWN.prototype._iterator = function (options) {
  return new MemIterator(this, options)
}

MemDOWN.prototype._isBuffer = function (obj) {
  return Buffer.isBuffer(obj)
}

MemDOWN.destroy = function (name, callback) {
  var key = '$' + name

  if (key in globalStore)
    delete globalStore[key]

  setImmediate(callback)
}

module.exports = MemDOWN

}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {},require("buffer").Buffer)
},{"_process":113,"abstract-leveldown":52,"buffer":105,"functional-red-black-tree":23,"inherits":28,"ltgt":54}],49:[function(require,module,exports){
arguments[4][12][0].apply(exports,arguments)
},{"_process":113,"dup":12}],50:[function(require,module,exports){
arguments[4][3][0].apply(exports,arguments)
},{"_process":113,"dup":3}],51:[function(require,module,exports){
arguments[4][14][0].apply(exports,arguments)
},{"../../../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js":110,"./abstract-chained-batch":49,"./abstract-iterator":50,"_process":113,"dup":14,"xtend":55}],52:[function(require,module,exports){
arguments[4][15][0].apply(exports,arguments)
},{"./abstract-chained-batch":49,"./abstract-iterator":50,"./abstract-leveldown":51,"./is-leveldown":53,"dup":15}],53:[function(require,module,exports){
arguments[4][16][0].apply(exports,arguments)
},{"./abstract-leveldown":51,"dup":16}],54:[function(require,module,exports){
(function (Buffer){

exports.compare = function (a, b) {

  if(Buffer.isBuffer(a)) {
    var l = Math.min(a.length, b.length)
    for(var i = 0; i < l; i++) {
      var cmp = a[i] - b[i]
      if(cmp) return cmp
    }
    return a.length - b.length
  }

  return a < b ? -1 : a > b ? 1 : 0
}

function has(obj, key) {
  return Object.hasOwnProperty.call(obj, key)
}

// to be compatible with the current abstract-leveldown tests
// nullish or empty strings.
// I could use !!val but I want to permit numbers and booleans,
// if possible.

function isDef (val) {
  return val != null && val !== ''
}

var lowerBound = exports.lowerBound = function (range) {
  return (
      isDef(range.gt)                      ? range.gt
    : isDef(range.gte)                     ? range.gte
    : isDef(range.min)                     ? range.min
    : isDef(range.start) && !range.reverse ? range.start
    : isDef(range.end) && range.reverse    ? range.end
    :                                        undefined
  )
}

exports.lowerBoundInclusive = function (range) {
  return isDef(range.gt) ? false : true
}

exports.upperBoundInclusive =
  function (range) {
    return isDef(range.lt) ? false : true
  }

var lowerBoundExclusive = exports.lowerBoundExclusive =
  function (range) {
    return isDef(range.gt) ? true : false
  }

var upperBoundExclusive = exports.upperBoundExclusive =
  function (range) {
    return isDef(range.lt) ? true : false
  }

var upperBound = exports.upperBound = function (range) {
  return (
      isDef(range.lt)                     ? range.lt
    : isDef(range.lte)                    ? range.lte
    : isDef(range.max)                    ? range.max
    : isDef(range.start) && range.reverse ? range.start
    : isDef(range.end) && !range.reverse  ? range.end
    :                                       undefined
  )
}


exports.contains = function (range, key, compare) {
  compare = compare || exports.compare

  var lb = lowerBound(range)
  if(isDef(lb)) {
    var cmp = compare(key, lb)
    if(cmp < 0 || (cmp === 0 && lowerBoundExclusive(range)))
      return false
  }

  var ub = upperBound(range)
  if(isDef(ub)) {
    var cmp = compare(key, ub)
    if(cmp > 0 || (cmp === 0) && upperBoundExclusive(range))
      return false
  }

  return true
}

exports.filter = function (range, compare) {
  return function (key) {
    return exports.contains(range, key, compare)
  }
}

}).call(this,{"isBuffer":require("../../../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js")})
},{"../../../../../../../../../../../../../../usr/local/lib/node_modules/browserify/node_modules/is-buffer/index.js":110}],55:[function(require,module,exports){
arguments[4][17][0].apply(exports,arguments)
},{"dup":17}],56:[function(require,module,exports){
/**
 * Helpers.
 */

var s = 1000;
var m = s * 60;
var h = m * 60;
var d = h * 24;
var y = d * 365.25;

/**
 * Parse or format the given `val`.
 *
 * Options:
 *
 *  - `long` verbose formatting [false]
 *
 * @param {String|Number} val
 * @param {Object} options
 * @return {String|Number}
 * @api public
 */

module.exports = function(val, options){
  options = options || {};
  if ('string' == typeof val) return parse(val);
  return options.long
    ? long(val)
    : short(val);
};

/**
 * Parse the given `str` and return milliseconds.
 *
 * @param {String} str
 * @return {Number}
 * @api private
 */

function parse(str) {
  str = '' + str;
  if (str.length > 10000) return;
  var match = /^((?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|years?|yrs?|y)?$/i.exec(str);
  if (!match) return;
  var n = parseFloat(match[1]);
  var type = (match[2] || 'ms').toLowerCase();
  switch (type) {
    case 'years':
    case 'year':
    case 'yrs':
    case 'yr':
    case 'y':
      return n * y;
    case 'days':
    case 'day':
    case 'd':
      return n * d;
    case 'hours':
    case 'hour':
    case 'hrs':
    case 'hr':
    case 'h':
      return n * h;
    case 'minutes':
    case 'minute':
    case 'mins':
    case 'min':
    case 'm':
      return n * m;
    case 'seconds':
    case 'second':
    case 'secs':
    case 'sec':
    case 's':
      return n * s;
    case 'milliseconds':
    case 'millisecond':
    case 'msecs':
    case 'msec':
    case 'ms':
      return n;
  }
}

/**
 * Short format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function short(ms) {
  if (ms >= d) return Math.round(ms / d) + 'd';
  if (ms >= h) return Math.round(ms / h) + 'h';
  if (ms >= m) return Math.round(ms / m) + 'm';
  if (ms >= s) return Math.round(ms / s) + 's';
  return ms + 'ms';
}

/**
 * Long format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function long(ms) {
  return plural(ms, d, 'day')
    || plural(ms, h, 'hour')
    || plural(ms, m, 'minute')
    || plural(ms, s, 'second')
    || ms + ' ms';
}

/**
 * Pluralization helper.
 */

function plural(ms, n, name) {
  if (ms < n) return;
  if (ms < n * 1.5) return Math.floor(ms / n) + ' ' + name;
  return Math.ceil(ms / n) + ' ' + name + 's';
}

},{}],57:[function(require,module,exports){
(function (process,Buffer){
'use strict';

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var levelup = _interopDefault(require('levelup'));
var sublevel = _interopDefault(require('sublevel-pouchdb'));
var through2 = require('through2');
var getArguments = _interopDefault(require('argsarray'));
var pouchdbCollections = require('pouchdb-collections');
var Deque = _interopDefault(require('double-ended-queue'));
var Promise = _interopDefault(require('pouchdb-promise'));
var pouchdbUtils = require('pouchdb-utils');
var pouchdbAdapterUtils = require('pouchdb-adapter-utils');
var pouchdbMerge = require('pouchdb-merge');
var pouchdbJson = require('pouchdb-json');
var pouchdbMd5 = require('pouchdb-md5');
var pouchdbBinaryUtils = require('pouchdb-binary-utils');
var pouchdbErrors = require('pouchdb-errors');

function readAsBlobOrBuffer(storedObject, type) {
  // In the browser, we've stored a binary string. This now comes back as a
  // browserified Node-style Buffer (implemented as a typed array),
  // but we want a Blob instead.
  var byteArray = new Uint8Array(storedObject);
  return pouchdbBinaryUtils.blob([byteArray], {type: type});
}

// In the browser, we store a binary string
function prepareAttachmentForStorage(attData, cb) {
  pouchdbBinaryUtils.readAsBinaryString(attData, cb);
}

function createEmptyBlobOrBuffer(type) {
  return pouchdbBinaryUtils.blob([''], {type: type});
}

// similar to an idb or websql transaction object
// designed to be passed around. basically just caches
// things in-memory and then does a big batch() operation
// when you're done

function getCacheFor(transaction, store) {
  var prefix = store.prefix()[0];
  var cache = transaction._cache;
  var subCache = cache.get(prefix);
  if (!subCache) {
    subCache = new pouchdbCollections.Map();
    cache.set(prefix, subCache);
  }
  return subCache;
}

function LevelTransaction() {
  this._batch = [];
  this._cache = new pouchdbCollections.Map();
}

LevelTransaction.prototype.get = function (store, key, callback) {
  var cache = getCacheFor(this, store);
  var exists = cache.get(key);
  if (exists) {
    return process.nextTick(function () {
      callback(null, exists);
    });
  } else if (exists === null) { // deleted marker
    /* istanbul ignore next */
    return process.nextTick(function () {
      callback({name: 'NotFoundError'});
    });
  }
  store.get(key, function (err, res) {
    if (err) {
      /* istanbul ignore else */
      if (err.name === 'NotFoundError') {
        cache.set(key, null);
      }
      return callback(err);
    }
    cache.set(key, res);
    callback(null, res);
  });
};

LevelTransaction.prototype.batch = function (batch) {
  for (var i = 0, len = batch.length; i < len; i++) {
    var operation = batch[i];

    var cache = getCacheFor(this, operation.prefix);

    if (operation.type === 'put') {
      cache.set(operation.key, operation.value);
    } else {
      cache.set(operation.key, null);
    }
  }
  this._batch = this._batch.concat(batch);
};

LevelTransaction.prototype.execute = function (db, callback) {

  var keys = new pouchdbCollections.Set();
  var uniqBatches = [];

  // remove duplicates; last one wins
  for (var i = this._batch.length - 1; i >= 0; i--) {
    var operation = this._batch[i];
    var lookupKey = operation.prefix.prefix()[0] + '\xff' + operation.key;
    if (keys.has(lookupKey)) {
      continue;
    }
    keys.add(lookupKey);
    uniqBatches.push(operation);
  }

  db.batch(uniqBatches, callback);
};

var DOC_STORE = 'document-store';
var BY_SEQ_STORE = 'by-sequence';
var ATTACHMENT_STORE = 'attach-store';
var BINARY_STORE = 'attach-binary-store';
var LOCAL_STORE = 'local-store';
var META_STORE = 'meta-store';

// leveldb barks if we try to open a db multiple times
// so we cache opened connections here for initstore()
var dbStores = new pouchdbCollections.Map();

// store the value of update_seq in the by-sequence store the key name will
// never conflict, since the keys in the by-sequence store are integers
var UPDATE_SEQ_KEY = '_local_last_update_seq';
var DOC_COUNT_KEY = '_local_doc_count';
var UUID_KEY = '_local_uuid';

var MD5_PREFIX = 'md5-';

var safeJsonEncoding = {
  encode: pouchdbJson.safeJsonStringify,
  decode: pouchdbJson.safeJsonParse,
  buffer: false,
  type: 'cheap-json'
};

var levelChanges = new pouchdbUtils.changesHandler();

// winningRev and deleted are performance-killers, but
// in newer versions of PouchDB, they are cached on the metadata
function getWinningRev(metadata) {
  return 'winningRev' in metadata ?
    metadata.winningRev : pouchdbMerge.winningRev(metadata);
}

function getIsDeleted(metadata, winningRev) {
  return 'deleted' in metadata ?
    metadata.deleted : pouchdbAdapterUtils.isDeleted(metadata, winningRev);
}

function fetchAttachment(att, stores, opts) {
  var type = att.content_type;
  return new Promise(function (resolve, reject) {
    stores.binaryStore.get(att.digest, function (err, buffer) {
      var data;
      if (err) {
        /* istanbul ignore if */
        if (err.name !== 'NotFoundError') {
          return reject(err);
        } else {
          // empty
          if (!opts.binary) {
            data = '';
          } else {
            data = pouchdbBinaryUtils.binaryStringToBlobOrBuffer('', type);
          }
        }
      } else { // non-empty
        if (opts.binary) {
          data = readAsBlobOrBuffer(buffer, type);
        } else {
          data = buffer.toString('base64');
        }
      }
      delete att.stub;
      delete att.length;
      att.data = data;
      resolve();
    });
  });
}

function fetchAttachments(results, stores, opts) {
  var atts = [];
  results.forEach(function (row) {
    if (!(row.doc && row.doc._attachments)) {
      return;
    }
    var attNames = Object.keys(row.doc._attachments);
    attNames.forEach(function (attName) {
      var att = row.doc._attachments[attName];
      if (!('data' in att)) {
        atts.push(att);
      }
    });
  });

  return Promise.all(atts.map(function (att) {
    return fetchAttachment(att, stores, opts);
  }));
}

function LevelPouch(opts, callback) {
  opts = pouchdbUtils.clone(opts);
  var api = this;
  var instanceId;
  var stores = {};
  var revLimit = opts.revs_limit;
  var db;
  var name = opts.name;
  // TODO: this is undocumented and unused probably
  /* istanbul ignore else */
  if (typeof opts.createIfMissing === 'undefined') {
    opts.createIfMissing = true;
  }

  var leveldown = opts.db;

  var dbStore;
  var leveldownName = pouchdbUtils.functionName(leveldown);
  if (dbStores.has(leveldownName)) {
    dbStore = dbStores.get(leveldownName);
  } else {
    dbStore = new pouchdbCollections.Map();
    dbStores.set(leveldownName, dbStore);
  }
  if (dbStore.has(name)) {
    db = dbStore.get(name);
    afterDBCreated();
  } else {
    dbStore.set(name, sublevel(levelup(name, opts, function (err) {
      /* istanbul ignore if */
      if (err) {
        dbStore.delete(name);
        return callback(err);
      }
      db = dbStore.get(name);
      db._docCount  = -1;
      db._queue = new Deque();
      /* istanbul ignore else */
      if (typeof opts.migrate === 'object') { // migration for leveldown
        opts.migrate.doMigrationOne(name, db, afterDBCreated);
      } else {
        afterDBCreated();
      }
    })));
  }

  function afterDBCreated() {
    stores.docStore = db.sublevel(DOC_STORE, {valueEncoding: safeJsonEncoding});
    stores.bySeqStore = db.sublevel(BY_SEQ_STORE, {valueEncoding: 'json'});
    stores.attachmentStore =
      db.sublevel(ATTACHMENT_STORE, {valueEncoding: 'json'});
    stores.binaryStore = db.sublevel(BINARY_STORE, {valueEncoding: 'binary'});
    stores.localStore = db.sublevel(LOCAL_STORE, {valueEncoding: 'json'});
    stores.metaStore = db.sublevel(META_STORE, {valueEncoding: 'json'});
    /* istanbul ignore else */
    if (typeof opts.migrate === 'object') { // migration for leveldown
      opts.migrate.doMigrationTwo(db, stores, afterLastMigration);
    } else {
      afterLastMigration();
    }
  }

  function afterLastMigration() {
    stores.metaStore.get(UPDATE_SEQ_KEY, function (err, value) {
      if (typeof db._updateSeq === 'undefined') {
        db._updateSeq = value || 0;
      }
      stores.metaStore.get(DOC_COUNT_KEY, function (err, value) {
        db._docCount = !err ? value : 0;
        stores.metaStore.get(UUID_KEY, function (err, value) {
          instanceId = !err ? value : pouchdbUtils.uuid();
          stores.metaStore.put(UUID_KEY, instanceId, function () {
            process.nextTick(function () {
              callback(null, api);
            });
          });
        });
      });
    });
  }

  function countDocs(callback) {
    /* istanbul ignore if */
    if (db.isClosed()) {
      return callback(new Error('database is closed'));
    }
    return callback(null, db._docCount); // use cached value
  }

  api.type = function () {
    return 'leveldb';
  };

  api._id = function (callback) {
    callback(null, instanceId);
  };

  api._info = function (callback) {
    var res = {
      doc_count: db._docCount,
      update_seq: db._updateSeq,
      backend_adapter: pouchdbUtils.functionName(leveldown)
    };
    return process.nextTick(function () {
      callback(null, res);
    });
  };

  function tryCode(fun, args) {
    try {
      fun.apply(null, args);
    } catch (err) {
      args[args.length - 1](err);
    }
  }

  function executeNext() {
    var firstTask = db._queue.peekFront();

    if (firstTask.type === 'read') {
      runReadOperation(firstTask);
    } else { // write, only do one at a time
      runWriteOperation(firstTask);
    }
  }

  function runReadOperation(firstTask) {
    // do multiple reads at once simultaneously, because it's safe

    var readTasks = [firstTask];
    var i = 1;
    var nextTask = db._queue.get(i);
    while (typeof nextTask !== 'undefined' && nextTask.type === 'read') {
      readTasks.push(nextTask);
      i++;
      nextTask = db._queue.get(i);
    }

    var numDone = 0;

    readTasks.forEach(function (readTask) {
      var args = readTask.args;
      var callback = args[args.length - 1];
      args[args.length - 1] = getArguments(function (cbArgs) {
        callback.apply(null, cbArgs);
        if (++numDone === readTasks.length) {
          process.nextTick(function () {
            // all read tasks have finished
            readTasks.forEach(function () {
              db._queue.shift();
            });
            if (db._queue.length) {
              executeNext();
            }
          });
        }
      });
      tryCode(readTask.fun, args);
    });
  }

  function runWriteOperation(firstTask) {
    var args = firstTask.args;
    var callback = args[args.length - 1];
    args[args.length - 1] = getArguments(function (cbArgs) {
      callback.apply(null, cbArgs);
      process.nextTick(function () {
        db._queue.shift();
        if (db._queue.length) {
          executeNext();
        }
      });
    });
    tryCode(firstTask.fun, args);
  }

  // all read/write operations to the database are done in a queue,
  // similar to how websql/idb works. this avoids problems such
  // as e.g. compaction needing to have a lock on the database while
  // it updates stuff. in the future we can revisit this.
  function writeLock(fun) {
    return getArguments(function (args) {
      db._queue.push({
        fun: fun,
        args: args,
        type: 'write'
      });

      if (db._queue.length === 1) {
        process.nextTick(executeNext);
      }
    });
  }

  // same as the writelock, but multiple can run at once
  function readLock(fun) {
    return getArguments(function (args) {
      db._queue.push({
        fun: fun,
        args: args,
        type: 'read'
      });

      if (db._queue.length === 1) {
        process.nextTick(executeNext);
      }
    });
  }

  function formatSeq(n) {
    return ('0000000000000000' + n).slice(-16);
  }

  function parseSeq(s) {
    return parseInt(s, 10);
  }

  api._get = readLock(function (id, opts, callback) {
    opts = pouchdbUtils.clone(opts);

    stores.docStore.get(id, function (err, metadata) {

      if (err || !metadata) {
        return callback(pouchdbErrors.createError(pouchdbErrors.MISSING_DOC, 'missing'));
      }

      var rev = getWinningRev(metadata);
      var deleted = getIsDeleted(metadata, rev);
      if (deleted && !opts.rev) {
        return callback(pouchdbErrors.createError(pouchdbErrors.MISSING_DOC, "deleted"));
      }

      rev = opts.rev ? opts.rev : rev;

      var seq = metadata.rev_map[rev];

      stores.bySeqStore.get(formatSeq(seq), function (err, doc) {
        if (!doc) {
          return callback(pouchdbErrors.createError(pouchdbErrors.MISSING_DOC));
        }
        /* istanbul ignore if */
        if ('_id' in doc && doc._id !== metadata.id) {
          // this failing implies something very wrong
          return callback(new Error('wrong doc returned'));
        }
        doc._id = metadata.id;
        if ('_rev' in doc) {
          /* istanbul ignore if */
          if (doc._rev !== rev) {
            // this failing implies something very wrong
            return callback(new Error('wrong doc returned'));
          }
        } else {
          // we didn't always store this
          doc._rev = rev;
        }
        return callback(null, {doc: doc, metadata: metadata});
      });
    });
  });

  // not technically part of the spec, but if putAttachment has its own
  // method...
  api._getAttachment = function (docId, attachId, attachment, opts, callback) {
    var digest = attachment.digest;
    var type = attachment.content_type;

    stores.binaryStore.get(digest, function (err, attach) {
      if (err) {
        /* istanbul ignore if */
        if (err.name !== 'NotFoundError') {
          return callback(err);
        }
        // Empty attachment
        return callback(null, opts.binary ? createEmptyBlobOrBuffer(type) : '');
      }

      if (opts.binary) {
        callback(null, readAsBlobOrBuffer(attach, type));
      } else {
        callback(null, attach.toString('base64'));
      }
    });
  };

  api._bulkDocs = writeLock(function (req, opts, callback) {
    var newEdits = opts.new_edits;
    var results = new Array(req.docs.length);
    var fetchedDocs = new pouchdbCollections.Map();
    var stemmedRevs = new pouchdbCollections.Map();

    var txn = new LevelTransaction();
    var docCountDelta = 0;
    var newUpdateSeq = db._updateSeq;

    // parse the docs and give each a sequence number
    var userDocs = req.docs;
    var docInfos = userDocs.map(function (doc) {
      if (doc._id && pouchdbAdapterUtils.isLocalId(doc._id)) {
        return doc;
      }
      var newDoc = pouchdbAdapterUtils.parseDoc(doc, newEdits);

      if (newDoc.metadata && !newDoc.metadata.rev_map) {
        newDoc.metadata.rev_map = {};
      }

      return newDoc;
    });
    var infoErrors = docInfos.filter(function (doc) {
      return doc.error;
    });

    if (infoErrors.length) {
      return callback(infoErrors[0]);
    }

    // verify any stub attachments as a precondition test

    function verifyAttachment(digest, callback) {
      txn.get(stores.attachmentStore, digest, function (levelErr) {
        if (levelErr) {
          var err = pouchdbErrors.createError(pouchdbErrors.MISSING_STUB,
                                'unknown stub attachment with digest ' +
                                digest);
          callback(err);
        } else {
          callback();
        }
      });
    }

    function verifyAttachments(finish) {
      var digests = [];
      userDocs.forEach(function (doc) {
        if (doc && doc._attachments) {
          Object.keys(doc._attachments).forEach(function (filename) {
            var att = doc._attachments[filename];
            if (att.stub) {
              digests.push(att.digest);
            }
          });
        }
      });
      if (!digests.length) {
        return finish();
      }
      var numDone = 0;
      var err;

      digests.forEach(function (digest) {
        verifyAttachment(digest, function (attErr) {
          if (attErr && !err) {
            err = attErr;
          }

          if (++numDone === digests.length) {
            finish(err);
          }
        });
      });
    }

    function fetchExistingDocs(finish) {
      var numDone = 0;
      var overallErr;
      function checkDone() {
        if (++numDone === userDocs.length) {
          return finish(overallErr);
        }
      }

      userDocs.forEach(function (doc) {
        if (doc._id && pouchdbAdapterUtils.isLocalId(doc._id)) {
          // skip local docs
          return checkDone();
        }
        txn.get(stores.docStore, doc._id, function (err, info) {
          if (err) {
            /* istanbul ignore if */
            if (err.name !== 'NotFoundError') {
              overallErr = err;
            }
          } else {
            fetchedDocs.set(doc._id, info);
          }
          checkDone();
        });
      });
    }

    function compact(revsMap, callback) {
      var promise = Promise.resolve();
      revsMap.forEach(function (revs, docId) {
        // TODO: parallelize, for now need to be sequential to
        // pass orphaned attachment tests
        promise = promise.then(function () {
          return new Promise(function (resolve, reject) {
            api._doCompactionNoLock(docId, revs, {ctx: txn}, function (err) {
              /* istanbul ignore if */
              if (err) {
                return reject(err);
              }
              resolve();
            });
          });
        });
      });

      promise.then(function () {
        callback();
      }, callback);
    }

    function autoCompact(callback) {
      var revsMap = new pouchdbCollections.Map();
      fetchedDocs.forEach(function (metadata, docId) {
        revsMap.set(docId, pouchdbMerge.compactTree(metadata));
      });
      compact(revsMap, callback);
    }

    function finish() {
      compact(stemmedRevs, function (error) {
        /* istanbul ignore if */
        if (error) {
          complete(error);
        }
        if (api.auto_compaction) {
          return autoCompact(complete);
        }
        complete();
      });
    }

    function writeDoc(docInfo, winningRev, winningRevIsDeleted, newRevIsDeleted,
                      isUpdate, delta, resultsIdx, callback2) {
      docCountDelta += delta;

      var err = null;
      var recv = 0;

      docInfo.metadata.winningRev = winningRev;
      docInfo.metadata.deleted = winningRevIsDeleted;

      docInfo.data._id = docInfo.metadata.id;
      docInfo.data._rev = docInfo.metadata.rev;

      if (newRevIsDeleted) {
        docInfo.data._deleted = true;
      }

      if (docInfo.stemmedRevs.length) {
        stemmedRevs.set(docInfo.metadata.id, docInfo.stemmedRevs);
      }

      var attachments = docInfo.data._attachments ?
        Object.keys(docInfo.data._attachments) :
        [];

      function attachmentSaved(attachmentErr) {
        recv++;
        if (!err) {
          /* istanbul ignore if */
          if (attachmentErr) {
            err = attachmentErr;
            callback2(err);
          } else if (recv === attachments.length) {
            finish();
          }
        }
      }

      function onMD5Load(doc, key, data, attachmentSaved) {
        return function (result) {
          saveAttachment(doc, MD5_PREFIX + result, key, data, attachmentSaved);
        };
      }

      function doMD5(doc, key, attachmentSaved) {
        return function (data) {
          pouchdbMd5.binaryMd5(data, onMD5Load(doc, key, data, attachmentSaved));
        };
      }

      for (var i = 0; i < attachments.length; i++) {
        var key = attachments[i];
        var att = docInfo.data._attachments[key];

        if (att.stub) {
          // still need to update the refs mapping
          var id = docInfo.data._id;
          var rev = docInfo.data._rev;
          saveAttachmentRefs(id, rev, att.digest, attachmentSaved);
          continue;
        }
        var data;
        if (typeof att.data === 'string') {
          // input is assumed to be a base64 string
          try {
            data = pouchdbBinaryUtils.atob(att.data);
          } catch (e) {
            callback(pouchdbErrors.createError(pouchdbErrors.BAD_ARG,
                     'Attachment is not a valid base64 string'));
            return;
          }
          doMD5(docInfo, key, attachmentSaved)(data);
        } else {
          prepareAttachmentForStorage(att.data,
            doMD5(docInfo, key, attachmentSaved));
        }
      }

      function finish() {
        var seq = docInfo.metadata.rev_map[docInfo.metadata.rev];
        /* istanbul ignore if */
        if (seq) {
          // check that there aren't any existing revisions with the same
          // revision id, else we shouldn't do anything
          return callback2();
        }
        seq = ++newUpdateSeq;
        docInfo.metadata.rev_map[docInfo.metadata.rev] =
          docInfo.metadata.seq = seq;
        var seqKey = formatSeq(seq);
        var batch = [{
          key: seqKey,
          value: docInfo.data,
          prefix: stores.bySeqStore,
          type: 'put'
        }, {
          key: docInfo.metadata.id,
          value: docInfo.metadata,
          prefix: stores.docStore,
          type: 'put'
        }];
        txn.batch(batch);
        results[resultsIdx] = {
          ok: true,
          id: docInfo.metadata.id,
          rev: winningRev
        };
        fetchedDocs.set(docInfo.metadata.id, docInfo.metadata);
        callback2();
      }

      if (!attachments.length) {
        finish();
      }
    }

    // attachments are queued per-digest, otherwise the refs could be
    // overwritten by concurrent writes in the same bulkDocs session
    var attachmentQueues = {};

    function saveAttachmentRefs(id, rev, digest, callback) {

      function fetchAtt() {
        return new Promise(function (resolve, reject) {
          txn.get(stores.attachmentStore, digest, function (err, oldAtt) {
            /* istanbul ignore if */
            if (err && err.name !== 'NotFoundError') {
              return reject(err);
            }
            resolve(oldAtt);
          });
        });
      }

      function saveAtt(oldAtt) {
        var ref = [id, rev].join('@');
        var newAtt = {};

        if (oldAtt) {
          if (oldAtt.refs) {
            // only update references if this attachment already has them
            // since we cannot migrate old style attachments here without
            // doing a full db scan for references
            newAtt.refs = oldAtt.refs;
            newAtt.refs[ref] = true;
          }
        } else {
          newAtt.refs = {};
          newAtt.refs[ref] = true;
        }

        return new Promise(function (resolve) {
          txn.batch([{
            type: 'put',
            prefix: stores.attachmentStore,
            key: digest,
            value: newAtt
          }]);
          resolve(!oldAtt);
        });
      }

      // put attachments in a per-digest queue, to avoid two docs with the same
      // attachment overwriting each other
      var queue = attachmentQueues[digest] || Promise.resolve();
      attachmentQueues[digest] = queue.then(function () {
        return fetchAtt().then(saveAtt).then(function (isNewAttachment) {
          callback(null, isNewAttachment);
        }, callback);
      });
    }

    function saveAttachment(docInfo, digest, key, data, callback) {
      var att = docInfo.data._attachments[key];
      delete att.data;
      att.digest = digest;
      att.length = data.length;
      var id = docInfo.metadata.id;
      var rev = docInfo.metadata.rev;
      att.revpos = parseInt(rev, 10);

      saveAttachmentRefs(id, rev, digest, function (err, isNewAttachment) {
        /* istanbul ignore if */
        if (err) {
          return callback(err);
        }
        // do not try to store empty attachments
        if (data.length === 0) {
          return callback(err);
        }
        if (!isNewAttachment) {
          // small optimization - don't bother writing it again
          return callback(err);
        }
        txn.batch([{
          type: 'put',
          prefix: stores.binaryStore,
          key: digest,
          value: new Buffer(data, 'binary')
        }]);
        callback();
      });
    }

    function complete(err) {
      /* istanbul ignore if */
      if (err) {
        return process.nextTick(function () {
          callback(err);
        });
      }
      txn.batch([
        {
          prefix: stores.metaStore,
          type: 'put',
          key: UPDATE_SEQ_KEY,
          value: newUpdateSeq
        },
        {
          prefix: stores.metaStore,
          type: 'put',
          key: DOC_COUNT_KEY,
          value: db._docCount + docCountDelta
        }
      ]);
      txn.execute(db, function (err) {
        /* istanbul ignore if */
        if (err) {
          return callback(err);
        }
        db._docCount += docCountDelta;
        db._updateSeq = newUpdateSeq;
        levelChanges.notify(name);
        process.nextTick(function () {
          callback(null, results);
        });
      });
    }

    if (!docInfos.length) {
      return callback(null, []);
    }

    verifyAttachments(function (err) {
      if (err) {
        return callback(err);
      }
      fetchExistingDocs(function (err) {
        /* istanbul ignore if */
        if (err) {
          return callback(err);
        }
        pouchdbAdapterUtils.processDocs(revLimit, docInfos, api, fetchedDocs, txn, results,
                    writeDoc, opts, finish);
      });
    });
  });
  api._allDocs = readLock(function (opts, callback) {
    opts = pouchdbUtils.clone(opts);
    countDocs(function (err, docCount) {
      /* istanbul ignore if */
      if (err) {
        return callback(err);
      }
      var readstreamOpts = {};
      var skip = opts.skip || 0;
      if (opts.startkey) {
        readstreamOpts.gte = opts.startkey;
      }
      if (opts.endkey) {
        readstreamOpts.lte = opts.endkey;
      }
      if (opts.key) {
        readstreamOpts.gte = readstreamOpts.lte = opts.key;
      }
      if (opts.descending) {
        readstreamOpts.reverse = true;
        // switch start and ends
        var tmp = readstreamOpts.lte;
        readstreamOpts.lte = readstreamOpts.gte;
        readstreamOpts.gte = tmp;
      }
      var limit;
      if (typeof opts.limit === 'number') {
        limit = opts.limit;
      }
      if (limit === 0 ||
          ('start' in readstreamOpts && 'end' in readstreamOpts &&
          readstreamOpts.start > readstreamOpts.end)) {
        // should return 0 results when start is greater than end.
        // normally level would "fix" this for us by reversing the order,
        // so short-circuit instead
        return callback(null, {
          total_rows: docCount,
          offset: opts.skip,
          rows: []
        });
      }
      var results = [];
      var docstream = stores.docStore.readStream(readstreamOpts);

      var throughStream = through2.obj(function (entry, _, next) {
        var metadata = entry.value;
        // winningRev and deleted are performance-killers, but
        // in newer versions of PouchDB, they are cached on the metadata
        var winningRev = getWinningRev(metadata);
        var deleted = getIsDeleted(metadata, winningRev);
        if (!deleted) {
          if (skip-- > 0) {
            next();
            return;
          } else if (typeof limit === 'number' && limit-- <= 0) {
            docstream.unpipe();
            docstream.destroy();
            next();
            return;
          }
        } else if (opts.deleted !== 'ok') {
          next();
          return;
        }
        function allDocsInner(data) {
          var doc = {
            id: metadata.id,
            key: metadata.id,
            value: {
              rev: winningRev
            }
          };
          if (opts.include_docs) {
            doc.doc = data;
            doc.doc._rev = doc.value.rev;
            if (opts.conflicts) {
              doc.doc._conflicts = pouchdbMerge.collectConflicts(metadata);
            }
            for (var att in doc.doc._attachments) {
              if (doc.doc._attachments.hasOwnProperty(att)) {
                doc.doc._attachments[att].stub = true;
              }
            }
          }
          if (opts.inclusive_end === false && metadata.id === opts.endkey) {
            return next();
          } else if (deleted) {
            if (opts.deleted === 'ok') {
              doc.value.deleted = true;
              doc.doc = null;
            } else {
              /* istanbul ignore next */
              return next();
            }
          }
          results.push(doc);
          next();
        }
        if (opts.include_docs) {
          var seq = metadata.rev_map[winningRev];
          stores.bySeqStore.get(formatSeq(seq), function (err, data) {
            allDocsInner(data);
          });
        }
        else {
          allDocsInner();
        }
      }, function (next) {
        Promise.resolve().then(function () {
          if (opts.include_docs && opts.attachments) {
            return fetchAttachments(results, stores, opts);
          }
        }).then(function () {
          callback(null, {
            total_rows: docCount,
            offset: opts.skip,
            rows: results
          });
        }, callback);
        next();
      }).on('unpipe', function () {
        throughStream.end();
      });

      docstream.on('error', callback);

      docstream.pipe(throughStream);
    });
  });

  api._changes = function (opts) {
    opts = pouchdbUtils.clone(opts);

    if (opts.continuous) {
      var id = name + ':' + pouchdbUtils.uuid();
      levelChanges.addListener(name, id, api, opts);
      levelChanges.notify(name);
      return {
        cancel: function () {
          levelChanges.removeListener(name, id);
        }
      };
    }

    var descending = opts.descending;
    var results = [];
    var lastSeq = opts.since || 0;
    var called = 0;
    var streamOpts = {
      reverse: descending
    };
    var limit;
    if ('limit' in opts && opts.limit > 0) {
      limit = opts.limit;
    }
    if (!streamOpts.reverse) {
      streamOpts.start = formatSeq(opts.since || 0);
    }

    var docIds = opts.doc_ids && new pouchdbCollections.Set(opts.doc_ids);
    var filter = pouchdbUtils.filterChange(opts);
    var docIdsToMetadata = new pouchdbCollections.Map();

    var returnDocs;
    if ('return_docs' in opts) {
      returnDocs = opts.return_docs;
    } else if ('returnDocs' in opts) {
      // TODO: Remove 'returnDocs' in favor of 'return_docs' in a future release
      returnDocs = opts.returnDocs;
    } else {
      returnDocs = true;
    }

    function complete() {
      opts.done = true;
      if (returnDocs && opts.limit) {
        /* istanbul ignore if */
        if (opts.limit < results.length) {
          results.length = opts.limit;
        }
      }
      changeStream.unpipe(throughStream);
      changeStream.destroy();
      if (!opts.continuous && !opts.cancelled) {
        if (opts.include_docs && opts.attachments) {
          fetchAttachments(results, stores, opts).then(function () {
            opts.complete(null, {results: results, last_seq: lastSeq});
          });
        } else {
          opts.complete(null, {results: results, last_seq: lastSeq});
        }
      }
    }
    var changeStream = stores.bySeqStore.readStream(streamOpts);
    var throughStream = through2.obj(function (data, _, next) {
      if (limit && called >= limit) {
        complete();
        return next();
      }
      if (opts.cancelled || opts.done) {
        return next();
      }

      var seq = parseSeq(data.key);
      var doc = data.value;

      if (seq === opts.since && !descending) {
        // couchdb ignores `since` if descending=true
        return next();
      }

      if (docIds && !docIds.has(doc._id)) {
        return next();
      }

      var metadata;

      function onGetMetadata(metadata) {
        var winningRev = getWinningRev(metadata);

        function onGetWinningDoc(winningDoc) {

          var change = opts.processChange(winningDoc, metadata, opts);
          change.seq = metadata.seq;

          var filtered = filter(change);
          if (typeof filtered === 'object') {
            return opts.complete(filtered);
          }

          if (filtered) {
            called++;

            if (opts.attachments && opts.include_docs) {
              // fetch attachment immediately for the benefit
              // of live listeners
              fetchAttachments([change], stores, opts).then(function () {
                opts.onChange(change);
              });
            } else {
              opts.onChange(change);
            }

            if (returnDocs) {
              results.push(change);
            }
          }
          next();
        }

        if (metadata.seq !== seq) {
          // some other seq is later
          return next();
        }

        lastSeq = seq;

        if (winningRev === doc._rev) {
          return onGetWinningDoc(doc);
        }

        // fetch the winner

        var winningSeq = metadata.rev_map[winningRev];

        stores.bySeqStore.get(formatSeq(winningSeq), function (err, doc) {
          onGetWinningDoc(doc);
        });
      }

      metadata = docIdsToMetadata.get(doc._id);
      if (metadata) { // cached
        return onGetMetadata(metadata);
      }
      // metadata not cached, have to go fetch it
      stores.docStore.get(doc._id, function (err, metadata) {
        /* istanbul ignore if */
        if (opts.cancelled || opts.done || db.isClosed() ||
          pouchdbAdapterUtils.isLocalId(metadata.id)) {
          return next();
        }
        docIdsToMetadata.set(doc._id, metadata);
        onGetMetadata(metadata);
      });
    }, function (next) {
      if (opts.cancelled) {
        return next();
      }
      if (returnDocs && opts.limit) {
        /* istanbul ignore if */
        if (opts.limit < results.length) {
          results.length = opts.limit;
        }
      }

      next();
    }).on('unpipe', function () {
      throughStream.end();
      complete();
    });
    changeStream.pipe(throughStream);
    return {
      cancel: function () {
        opts.cancelled = true;
        complete();
      }
    };
  };

  api._close = function (callback) {
    /* istanbul ignore if */
    if (db.isClosed()) {
      return callback(pouchdbErrors.createError(pouchdbErrors.NOT_OPEN));
    }
    db.close(function (err) {
      /* istanbul ignore if */
      if (err) {
        callback(err);
      } else {
        dbStore.delete(name);
        callback();
      }
    });
  };

  api._getRevisionTree = function (docId, callback) {
    stores.docStore.get(docId, function (err, metadata) {
      if (err) {
        callback(pouchdbErrors.createError(pouchdbErrors.MISSING_DOC));
      } else {
        callback(null, metadata.rev_tree);
      }
    });
  };

  api._doCompaction = writeLock(function (docId, revs, opts, callback) {
    api._doCompactionNoLock(docId, revs, opts, callback);
  });

  // the NoLock version is for use by bulkDocs
  api._doCompactionNoLock = function (docId, revs, opts, callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }

    if (!revs.length) {
      return callback();
    }
    var txn = opts.ctx || new LevelTransaction();

    txn.get(stores.docStore, docId, function (err, metadata) {
      /* istanbul ignore if */
      if (err) {
        return callback(err);
      }
      var seqs = revs.map(function (rev) {
        var seq = metadata.rev_map[rev];
        delete metadata.rev_map[rev];
        return seq;
      });
      pouchdbMerge.traverseRevTree(metadata.rev_tree, function (isLeaf, pos,
                                                         revHash, ctx, opts) {
        var rev = pos + '-' + revHash;
        if (revs.indexOf(rev) !== -1) {
          opts.status = 'missing';
        }
      });

      var batch = [];
      batch.push({
        key: metadata.id,
        value: metadata,
        type: 'put',
        prefix: stores.docStore
      });

      var digestMap = {};
      var numDone = 0;
      var overallErr;
      function checkDone(err) {
        /* istanbul ignore if */
        if (err) {
          overallErr = err;
        }
        if (++numDone === revs.length) { // done
          /* istanbul ignore if */
          if (overallErr) {
            return callback(overallErr);
          }
          deleteOrphanedAttachments();
        }
      }

      function finish(err) {
        /* istanbul ignore if */
        if (err) {
          return callback(err);
        }
        txn.batch(batch);
        if (opts.ctx) {
          // don't execute immediately
          return callback();
        }
        txn.execute(db, callback);
      }

      function deleteOrphanedAttachments() {
        var possiblyOrphanedAttachments = Object.keys(digestMap);
        if (!possiblyOrphanedAttachments.length) {
          return finish();
        }
        var numDone = 0;
        var overallErr;
        function checkDone(err) {
          /* istanbul ignore if */
          if (err) {
            overallErr = err;
          }
          if (++numDone === possiblyOrphanedAttachments.length) {
            finish(overallErr);
          }
        }
        var refsToDelete = new pouchdbCollections.Map();
        revs.forEach(function (rev) {
          refsToDelete.set(docId + '@' + rev, true);
        });
        possiblyOrphanedAttachments.forEach(function (digest) {
          txn.get(stores.attachmentStore, digest, function (err, attData) {
            /* istanbul ignore if */
            if (err) {
              if (err.name === 'NotFoundError') {
                return checkDone();
              } else {
                return checkDone(err);
              }
            }
            var refs = Object.keys(attData.refs || {}).filter(function (ref) {
              return !refsToDelete.has(ref);
            });
            var newRefs = {};
            refs.forEach(function (ref) {
              newRefs[ref] = true;
            });
            if (refs.length) { // not orphaned
              batch.push({
                key: digest,
                type: 'put',
                value: {refs: newRefs},
                prefix: stores.attachmentStore
              });
            } else { // orphaned, can safely delete
              batch = batch.concat([{
                key: digest,
                type: 'del',
                prefix: stores.attachmentStore
              }, {
                key: digest,
                type: 'del',
                prefix: stores.binaryStore
              }]);
            }
            checkDone();
          });
        });
      }

      seqs.forEach(function (seq) {
        batch.push({
          key: formatSeq(seq),
          type: 'del',
          prefix: stores.bySeqStore
        });
        txn.get(stores.bySeqStore, formatSeq(seq), function (err, doc) {
          /* istanbul ignore if */
          if (err) {
            if (err.name === 'NotFoundError') {
              return checkDone();
            } else {
              return checkDone(err);
            }
          }
          var atts = Object.keys(doc._attachments || {});
          atts.forEach(function (attName) {
            var digest = doc._attachments[attName].digest;
            digestMap[digest] = true;
          });
          checkDone();
        });
      });
    });
  };

  api._getLocal = function (id, callback) {
    stores.localStore.get(id, function (err, doc) {
      if (err) {
        callback(pouchdbErrors.createError(pouchdbErrors.MISSING_DOC));
      } else {
        callback(null, doc);
      }
    });
  };

  api._putLocal = function (doc, opts, callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    if (opts.ctx) {
      api._putLocalNoLock(doc, opts, callback);
    } else {
      api._putLocalWithLock(doc, opts, callback);
    }
  };

  api._putLocalWithLock = writeLock(function (doc, opts, callback) {
    api._putLocalNoLock(doc, opts, callback);
  });

  // the NoLock version is for use by bulkDocs
  api._putLocalNoLock = function (doc, opts, callback) {
    delete doc._revisions; // ignore this, trust the rev
    var oldRev = doc._rev;
    var id = doc._id;

    var txn = opts.ctx || new LevelTransaction();

    txn.get(stores.localStore, id, function (err, resp) {
      if (err && oldRev) {
        return callback(pouchdbErrors.createError(pouchdbErrors.REV_CONFLICT));
      }
      if (resp && resp._rev !== oldRev) {
        return callback(pouchdbErrors.createError(pouchdbErrors.REV_CONFLICT));
      }
      doc._rev =
          oldRev ? '0-' + (parseInt(oldRev.split('-')[1], 10) + 1) : '0-1';
      var batch = [
        {
          type: 'put',
          prefix: stores.localStore,
          key: id,
          value: doc
        }
      ];

      txn.batch(batch);
      var ret = {ok: true, id: doc._id, rev: doc._rev};

      if (opts.ctx) {
        // don't execute immediately
        return callback(null, ret);
      }
      txn.execute(db, function (err) {
        /* istanbul ignore if */
        if (err) {
          return callback(err);
        }
        callback(null, ret);
      });
    });
  };

  api._removeLocal = function (doc, opts, callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    if (opts.ctx) {
      api._removeLocalNoLock(doc, opts, callback);
    } else {
      api._removeLocalWithLock(doc, opts, callback);
    }
  };

  api._removeLocalWithLock = writeLock(function (doc, opts, callback) {
    api._removeLocalNoLock(doc, opts, callback);
  });

  // the NoLock version is for use by bulkDocs
  api._removeLocalNoLock = function (doc, opts, callback) {
    var txn = opts.ctx || new LevelTransaction();
    txn.get(stores.localStore, doc._id, function (err, resp) {
      if (err) {
        /* istanbul ignore if */
        if (err.name !== 'NotFoundError') {
          return callback(err);
        } else {
          return callback(pouchdbErrors.createError(pouchdbErrors.MISSING_DOC));
        }
      }
      if (resp._rev !== doc._rev) {
        return callback(pouchdbErrors.createError(pouchdbErrors.REV_CONFLICT));
      }
      txn.batch([{
        prefix: stores.localStore,
        type: 'del',
        key: doc._id
      }]);
      var ret = {ok: true, id: doc._id, rev: '0-0'};
      if (opts.ctx) {
        // don't execute immediately
        return callback(null, ret);
      }
      txn.execute(db, function (err) {
        /* istanbul ignore if */
        if (err) {
          return callback(err);
        }
        callback(null, ret);
      });
    });
  };

  // close and delete open leveldb stores
  api._destroy = function (opts, callback) {
    var dbStore;
    var leveldownName = pouchdbUtils.functionName(leveldown);
    /* istanbul ignore else */
    if (dbStores.has(leveldownName)) {
      dbStore = dbStores.get(leveldownName);
    } else {
      return callDestroy(name, callback);
    }

    /* istanbul ignore else */
    if (dbStore.has(name)) {
      levelChanges.removeAllListeners(name);

      dbStore.get(name).close(function () {
        dbStore.delete(name);
        callDestroy(name, callback);
      });
    } else {
      callDestroy(name, callback);
    }
  };
  function callDestroy(name, cb) {
    leveldown.destroy(name, cb);
  }
}

module.exports = LevelPouch;
}).call(this,require('_process'),require("buffer").Buffer)
},{"_process":113,"argsarray":5,"buffer":105,"double-ended-queue":18,"levelup":36,"pouchdb-adapter-utils":60,"pouchdb-binary-utils":61,"pouchdb-collections":63,"pouchdb-errors":64,"pouchdb-json":65,"pouchdb-md5":66,"pouchdb-merge":67,"pouchdb-promise":68,"pouchdb-utils":69,"sublevel-pouchdb":81,"through2":97}],58:[function(require,module,exports){
'use strict';

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var CoreLevelPouch = _interopDefault(require('pouchdb-adapter-leveldb-core'));
var pouchdbUtils = require('pouchdb-utils');
var localstoragedown = _interopDefault(require('localstorage-down'));

function LocalStoragePouch(opts, callback) {
  var _opts = pouchdbUtils.jsExtend({
    db: localstoragedown
  }, opts);

  CoreLevelPouch.call(this, _opts, callback);
}

// overrides for normal LevelDB behavior on Node
LocalStoragePouch.valid = function () {
  return typeof localStorage !== 'undefined';
};
LocalStoragePouch.use_prefix = true;

function index (PouchDB) {
  PouchDB.adapter('localstorage', LocalStoragePouch, true);
}

module.exports = index;
},{"localstorage-down":41,"pouchdb-adapter-leveldb-core":57,"pouchdb-utils":69}],59:[function(require,module,exports){
'use strict';

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var CoreLevelPouch = _interopDefault(require('pouchdb-adapter-leveldb-core'));
var pouchdbUtils = require('pouchdb-utils');
var memdown = _interopDefault(require('memdown'));

function MemDownPouch(opts, callback) {
  var _opts = pouchdbUtils.jsExtend({
    db: memdown
  }, opts);

  CoreLevelPouch.call(this, _opts, callback);
}

// overrides for normal LevelDB behavior on Node
MemDownPouch.valid = function () {
  return true;
};
MemDownPouch.use_prefix = false;

function index (PouchDB) {
  PouchDB.adapter('memory', MemDownPouch, true);
}

module.exports = index;
},{"memdown":48,"pouchdb-adapter-leveldb-core":57,"pouchdb-utils":69}],60:[function(require,module,exports){
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var pouchdbUtils = require('pouchdb-utils');
var pouchdbErrors = require('pouchdb-errors');
var pouchdbMerge = require('pouchdb-merge');
var pouchdbBinaryUtils = require('pouchdb-binary-utils');
var pouchdbMd5 = require('pouchdb-md5');
var pouchdbCollections = require('pouchdb-collections');

function toObject(array) {
  return array.reduce(function (obj, item) {
    obj[item] = true;
    return obj;
  }, {});
}
// List of top level reserved words for doc
var reservedWords = toObject([
  '_id',
  '_rev',
  '_attachments',
  '_deleted',
  '_revisions',
  '_revs_info',
  '_conflicts',
  '_deleted_conflicts',
  '_local_seq',
  '_rev_tree',
  //replication documents
  '_replication_id',
  '_replication_state',
  '_replication_state_time',
  '_replication_state_reason',
  '_replication_stats',
  // Specific to Couchbase Sync Gateway
  '_removed'
]);

// List of reserved words that should end up the document
var dataWords = toObject([
  '_attachments',
  //replication documents
  '_replication_id',
  '_replication_state',
  '_replication_state_time',
  '_replication_state_reason',
  '_replication_stats'
]);

function parseRevisionInfo(rev) {
  if (!/^\d+\-./.test(rev)) {
    return pouchdbErrors.createError(pouchdbErrors.INVALID_REV);
  }
  var idx = rev.indexOf('-');
  var left = rev.substring(0, idx);
  var right = rev.substring(idx + 1);
  return {
    prefix: parseInt(left, 10),
    id: right
  };
}

function makeRevTreeFromRevisions(revisions, opts) {
  var pos = revisions.start - revisions.ids.length + 1;

  var revisionIds = revisions.ids;
  var ids = [revisionIds[0], opts, []];

  for (var i = 1, len = revisionIds.length; i < len; i++) {
    ids = [revisionIds[i], {status: 'missing'}, [ids]];
  }

  return [{
    pos: pos,
    ids: ids
  }];
}

// Preprocess documents, parse their revisions, assign an id and a
// revision for new writes that are missing them, etc
function parseDoc(doc, newEdits) {

  var nRevNum;
  var newRevId;
  var revInfo;
  var opts = {status: 'available'};
  if (doc._deleted) {
    opts.deleted = true;
  }

  if (newEdits) {
    if (!doc._id) {
      doc._id = pouchdbUtils.uuid();
    }
    newRevId = pouchdbUtils.uuid(32, 16).toLowerCase();
    if (doc._rev) {
      revInfo = parseRevisionInfo(doc._rev);
      if (revInfo.error) {
        return revInfo;
      }
      doc._rev_tree = [{
        pos: revInfo.prefix,
        ids: [revInfo.id, {status: 'missing'}, [[newRevId, opts, []]]]
      }];
      nRevNum = revInfo.prefix + 1;
    } else {
      doc._rev_tree = [{
        pos: 1,
        ids : [newRevId, opts, []]
      }];
      nRevNum = 1;
    }
  } else {
    if (doc._revisions) {
      doc._rev_tree = makeRevTreeFromRevisions(doc._revisions, opts);
      nRevNum = doc._revisions.start;
      newRevId = doc._revisions.ids[0];
    }
    if (!doc._rev_tree) {
      revInfo = parseRevisionInfo(doc._rev);
      if (revInfo.error) {
        return revInfo;
      }
      nRevNum = revInfo.prefix;
      newRevId = revInfo.id;
      doc._rev_tree = [{
        pos: nRevNum,
        ids: [newRevId, opts, []]
      }];
    }
  }

  pouchdbUtils.invalidIdError(doc._id);

  doc._rev = nRevNum + '-' + newRevId;

  var result = {metadata : {}, data : {}};
  for (var key in doc) {
    /* istanbul ignore else */
    if (Object.prototype.hasOwnProperty.call(doc, key)) {
      var specialKey = key[0] === '_';
      if (specialKey && !reservedWords[key]) {
        var error = pouchdbErrors.createError(pouchdbErrors.DOC_VALIDATION, key);
        error.message = pouchdbErrors.DOC_VALIDATION.message + ': ' + key;
        throw error;
      } else if (specialKey && !dataWords[key]) {
        result.metadata[key.slice(1)] = doc[key];
      } else {
        result.data[key] = doc[key];
      }
    }
  }
  return result;
}

function parseBase64(data) {
  try {
    return pouchdbBinaryUtils.atob(data);
  } catch (e) {
    var err = pouchdbErrors.createError(pouchdbErrors.BAD_ARG,
      'Attachment is not a valid base64 string');
    return {error: err};
  }
}

function preprocessString(att, blobType, callback) {
  var asBinary = parseBase64(att.data);
  if (asBinary.error) {
    return callback(asBinary.error);
  }

  att.length = asBinary.length;
  if (blobType === 'blob') {
    att.data = pouchdbBinaryUtils.binaryStringToBlobOrBuffer(asBinary, att.content_type);
  } else if (blobType === 'base64') {
    att.data = pouchdbBinaryUtils.btoa(asBinary);
  } else { // binary
    att.data = asBinary;
  }
  pouchdbMd5.binaryMd5(asBinary, function (result) {
    att.digest = 'md5-' + result;
    callback();
  });
}

function preprocessBlob(att, blobType, callback) {
  pouchdbMd5.binaryMd5(att.data, function (md5) {
    att.digest = 'md5-' + md5;
    // size is for blobs (browser), length is for buffers (node)
    att.length = att.data.size || att.data.length || 0;
    if (blobType === 'binary') {
      pouchdbBinaryUtils.blobOrBufferToBinaryString(att.data, function (binString) {
        att.data = binString;
        callback();
      });
    } else if (blobType === 'base64') {
      pouchdbBinaryUtils.blobOrBufferToBase64(att.data, function (b64) {
        att.data = b64;
        callback();
      });
    } else {
      callback();
    }
  });
}

function preprocessAttachment(att, blobType, callback) {
  if (att.stub) {
    return callback();
  }
  if (typeof att.data === 'string') { // input is a base64 string
    preprocessString(att, blobType, callback);
  } else { // input is a blob
    preprocessBlob(att, blobType, callback);
  }
}

function preprocessAttachments(docInfos, blobType, callback) {

  if (!docInfos.length) {
    return callback();
  }

  var docv = 0;
  var overallErr;

  docInfos.forEach(function (docInfo) {
    var attachments = docInfo.data && docInfo.data._attachments ?
      Object.keys(docInfo.data._attachments) : [];
    var recv = 0;

    if (!attachments.length) {
      return done();
    }

    function processedAttachment(err) {
      overallErr = err;
      recv++;
      if (recv === attachments.length) {
        done();
      }
    }

    for (var key in docInfo.data._attachments) {
      if (docInfo.data._attachments.hasOwnProperty(key)) {
        preprocessAttachment(docInfo.data._attachments[key],
          blobType, processedAttachment);
      }
    }
  });

  function done() {
    docv++;
    if (docInfos.length === docv) {
      if (overallErr) {
        callback(overallErr);
      } else {
        callback();
      }
    }
  }
}

function updateDoc(revLimit, prev, docInfo, results,
                   i, cb, writeDoc, newEdits) {

  if (pouchdbMerge.revExists(prev.rev_tree, docInfo.metadata.rev)) {
    results[i] = docInfo;
    return cb();
  }

  // sometimes this is pre-calculated. historically not always
  var previousWinningRev = prev.winningRev || pouchdbMerge.winningRev(prev);
  var previouslyDeleted = 'deleted' in prev ? prev.deleted :
    pouchdbMerge.isDeleted(prev, previousWinningRev);
  var deleted = 'deleted' in docInfo.metadata ? docInfo.metadata.deleted :
    pouchdbMerge.isDeleted(docInfo.metadata);
  var isRoot = /^1-/.test(docInfo.metadata.rev);

  if (previouslyDeleted && !deleted && newEdits && isRoot) {
    var newDoc = docInfo.data;
    newDoc._rev = previousWinningRev;
    newDoc._id = docInfo.metadata.id;
    docInfo = parseDoc(newDoc, newEdits);
  }

  var merged = pouchdbMerge.merge(prev.rev_tree, docInfo.metadata.rev_tree[0], revLimit);

  var inConflict = newEdits && (((previouslyDeleted && deleted) ||
    (!previouslyDeleted && merged.conflicts !== 'new_leaf') ||
    (previouslyDeleted && !deleted && merged.conflicts === 'new_branch')));

  if (inConflict) {
    var err = pouchdbErrors.createError(pouchdbErrors.REV_CONFLICT);
    results[i] = err;
    return cb();
  }

  var newRev = docInfo.metadata.rev;
  docInfo.metadata.rev_tree = merged.tree;
  docInfo.stemmedRevs = merged.stemmedRevs || [];
  /* istanbul ignore else */
  if (prev.rev_map) {
    docInfo.metadata.rev_map = prev.rev_map; // used only by leveldb
  }

  // recalculate
  var winningRev = pouchdbMerge.winningRev(docInfo.metadata);
  var winningRevIsDeleted = pouchdbMerge.isDeleted(docInfo.metadata, winningRev);

  // calculate the total number of documents that were added/removed,
  // from the perspective of total_rows/doc_count
  var delta = (previouslyDeleted === winningRevIsDeleted) ? 0 :
    previouslyDeleted < winningRevIsDeleted ? -1 : 1;

  var newRevIsDeleted;
  if (newRev === winningRev) {
    // if the new rev is the same as the winning rev, we can reuse that value
    newRevIsDeleted = winningRevIsDeleted;
  } else {
    // if they're not the same, then we need to recalculate
    newRevIsDeleted = pouchdbMerge.isDeleted(docInfo.metadata, newRev);
  }

  writeDoc(docInfo, winningRev, winningRevIsDeleted, newRevIsDeleted,
    true, delta, i, cb);
}

function rootIsMissing(docInfo) {
  return docInfo.metadata.rev_tree[0].ids[1].status === 'missing';
}

function processDocs(revLimit, docInfos, api, fetchedDocs, tx, results,
                     writeDoc, opts, overallCallback) {

  // Default to 1000 locally
  revLimit = revLimit || 1000;

  function insertDoc(docInfo, resultsIdx, callback) {
    // Cant insert new deleted documents
    var winningRev = pouchdbMerge.winningRev(docInfo.metadata);
    var deleted = pouchdbMerge.isDeleted(docInfo.metadata, winningRev);
    if ('was_delete' in opts && deleted) {
      results[resultsIdx] = pouchdbErrors.createError(pouchdbErrors.MISSING_DOC, 'deleted');
      return callback();
    }

    // 4712 - detect whether a new document was inserted with a _rev
    var inConflict = newEdits && rootIsMissing(docInfo);

    if (inConflict) {
      var err = pouchdbErrors.createError(pouchdbErrors.REV_CONFLICT);
      results[resultsIdx] = err;
      return callback();
    }

    var delta = deleted ? 0 : 1;

    writeDoc(docInfo, winningRev, deleted, deleted, false,
      delta, resultsIdx, callback);
  }

  var newEdits = opts.new_edits;
  var idsToDocs = new pouchdbCollections.Map();

  var docsDone = 0;
  var docsToDo = docInfos.length;

  function checkAllDocsDone() {
    if (++docsDone === docsToDo && overallCallback) {
      overallCallback();
    }
  }

  docInfos.forEach(function (currentDoc, resultsIdx) {

    if (currentDoc._id && pouchdbMerge.isLocalId(currentDoc._id)) {
      var fun = currentDoc._deleted ? '_removeLocal' : '_putLocal';
      api[fun](currentDoc, {ctx: tx}, function (err, res) {
        results[resultsIdx] = err || res;
        checkAllDocsDone();
      });
      return;
    }

    var id = currentDoc.metadata.id;
    if (idsToDocs.has(id)) {
      docsToDo--; // duplicate
      idsToDocs.get(id).push([currentDoc, resultsIdx]);
    } else {
      idsToDocs.set(id, [[currentDoc, resultsIdx]]);
    }
  });

  // in the case of new_edits, the user can provide multiple docs
  // with the same id. these need to be processed sequentially
  idsToDocs.forEach(function (docs, id) {
    var numDone = 0;

    function docWritten() {
      if (++numDone < docs.length) {
        nextDoc();
      } else {
        checkAllDocsDone();
      }
    }
    function nextDoc() {
      var value = docs[numDone];
      var currentDoc = value[0];
      var resultsIdx = value[1];

      if (fetchedDocs.has(id)) {
        updateDoc(revLimit, fetchedDocs.get(id), currentDoc, results,
          resultsIdx, docWritten, writeDoc, newEdits);
      } else {
        // Ensure stemming applies to new writes as well
        var merged = pouchdbMerge.merge([], currentDoc.metadata.rev_tree[0], revLimit);
        currentDoc.metadata.rev_tree = merged.tree;
        currentDoc.stemmedRevs = merged.stemmedRevs || [];
        insertDoc(currentDoc, resultsIdx, docWritten);
      }
    }
    nextDoc();
  });
}

exports.invalidIdError = pouchdbUtils.invalidIdError;
exports.isDeleted = pouchdbMerge.isDeleted;
exports.isLocalId = pouchdbMerge.isLocalId;
exports.normalizeDdocFunctionName = pouchdbUtils.normalizeDdocFunctionName;
exports.parseDdocFunctionName = pouchdbUtils.parseDdocFunctionName;
exports.parseDoc = parseDoc;
exports.preprocessAttachments = preprocessAttachments;
exports.processDocs = processDocs;
exports.updateDoc = updateDoc;
},{"pouchdb-binary-utils":61,"pouchdb-collections":63,"pouchdb-errors":64,"pouchdb-md5":66,"pouchdb-merge":67,"pouchdb-utils":69}],61:[function(require,module,exports){
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var atob$1 = function (str) {
  return atob(str);
};

var btoa$1 = function (str) {
  return btoa(str);
};

// Abstracts constructing a Blob object, so it also works in older
// browsers that don't support the native Blob constructor (e.g.
// old QtWebKit versions, Android < 4.4).
function createBlob(parts, properties) {
  /* global BlobBuilder,MSBlobBuilder,MozBlobBuilder,WebKitBlobBuilder */
  parts = parts || [];
  properties = properties || {};
  try {
    return new Blob(parts, properties);
  } catch (e) {
    if (e.name !== "TypeError") {
      throw e;
    }
    var Builder = typeof BlobBuilder !== 'undefined' ? BlobBuilder :
                  typeof MSBlobBuilder !== 'undefined' ? MSBlobBuilder :
                  typeof MozBlobBuilder !== 'undefined' ? MozBlobBuilder :
                  WebKitBlobBuilder;
    var builder = new Builder();
    for (var i = 0; i < parts.length; i += 1) {
      builder.append(parts[i]);
    }
    return builder.getBlob(properties.type);
  }
}

// From http://stackoverflow.com/questions/14967647/ (continues on next line)
// encode-decode-image-with-base64-breaks-image (2013-04-21)
function binaryStringToArrayBuffer(bin) {
  var length = bin.length;
  var buf = new ArrayBuffer(length);
  var arr = new Uint8Array(buf);
  for (var i = 0; i < length; i++) {
    arr[i] = bin.charCodeAt(i);
  }
  return buf;
}

function binStringToBluffer(binString, type) {
  return createBlob([binaryStringToArrayBuffer(binString)], {type: type});
}

function b64ToBluffer(b64, type) {
  return binStringToBluffer(atob$1(b64), type);
}

//Can't find original post, but this is close
//http://stackoverflow.com/questions/6965107/ (continues on next line)
//converting-between-strings-and-arraybuffers
function arrayBufferToBinaryString(buffer) {
  var binary = '';
  var bytes = new Uint8Array(buffer);
  var length = bytes.byteLength;
  for (var i = 0; i < length; i++) {
    binary += String.fromCharCode(bytes[i]);
  }
  return binary;
}

// shim for browsers that don't support it
function readAsBinaryString(blob, callback) {
  if (typeof FileReader === 'undefined') {
    // fix for Firefox in a web worker
    // https://bugzilla.mozilla.org/show_bug.cgi?id=901097
    return callback(arrayBufferToBinaryString(
      new FileReaderSync().readAsArrayBuffer(blob)));
  }

  var reader = new FileReader();
  var hasBinaryString = typeof reader.readAsBinaryString === 'function';
  reader.onloadend = function (e) {
    var result = e.target.result || '';
    if (hasBinaryString) {
      return callback(result);
    }
    callback(arrayBufferToBinaryString(result));
  };
  if (hasBinaryString) {
    reader.readAsBinaryString(blob);
  } else {
    reader.readAsArrayBuffer(blob);
  }
}

function blobToBinaryString(blobOrBuffer, callback) {
  readAsBinaryString(blobOrBuffer, function (bin) {
    callback(bin);
  });
}

function blobToBase64(blobOrBuffer, callback) {
  blobToBinaryString(blobOrBuffer, function (base64) {
    callback(btoa$1(base64));
  });
}

// simplified API. universal browser support is assumed
function readAsArrayBuffer(blob, callback) {
  if (typeof FileReader === 'undefined') {
    // fix for Firefox in a web worker:
    // https://bugzilla.mozilla.org/show_bug.cgi?id=901097
    return callback(new FileReaderSync().readAsArrayBuffer(blob));
  }

  var reader = new FileReader();
  reader.onloadend = function (e) {
    var result = e.target.result || new ArrayBuffer(0);
    callback(result);
  };
  reader.readAsArrayBuffer(blob);
}

// this is not used in the browser
function typedBuffer() {
}

exports.atob = atob$1;
exports.btoa = btoa$1;
exports.base64StringToBlobOrBuffer = b64ToBluffer;
exports.binaryStringToArrayBuffer = binaryStringToArrayBuffer;
exports.binaryStringToBlobOrBuffer = binStringToBluffer;
exports.blob = createBlob;
exports.blobOrBufferToBase64 = blobToBase64;
exports.blobOrBufferToBinaryString = blobToBinaryString;
exports.readAsArrayBuffer = readAsArrayBuffer;
exports.readAsBinaryString = readAsBinaryString;
exports.typedBuffer = typedBuffer;
},{}],62:[function(require,module,exports){
(function (process,global){
'use strict';

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var lie = _interopDefault(require('lie'));
var getArguments = _interopDefault(require('argsarray'));
var debug = _interopDefault(require('debug'));
var events = require('events');
var inherits = _interopDefault(require('inherits'));
var scopedEval = _interopDefault(require('scope-eval'));
var Md5 = _interopDefault(require('spark-md5'));
var vuvuzela = _interopDefault(require('vuvuzela'));
var PromisePool = _interopDefault(require('es6-promise-pool'));

/* istanbul ignore next */
var PouchPromise = typeof Promise === 'function' ? Promise : lie;

function isBinaryObject(object) {
  return (typeof ArrayBuffer !== 'undefined' && object instanceof ArrayBuffer) ||
    (typeof Blob !== 'undefined' && object instanceof Blob);
}

function cloneArrayBuffer(buff) {
  if (typeof buff.slice === 'function') {
    return buff.slice(0);
  }
  // IE10-11 slice() polyfill
  var target = new ArrayBuffer(buff.byteLength);
  var targetArray = new Uint8Array(target);
  var sourceArray = new Uint8Array(buff);
  targetArray.set(sourceArray);
  return target;
}

function cloneBinaryObject(object) {
  if (object instanceof ArrayBuffer) {
    return cloneArrayBuffer(object);
  }
  var size = object.size;
  var type = object.type;
  // Blob
  if (typeof object.slice === 'function') {
    return object.slice(0, size, type);
  }
  // PhantomJS slice() replacement
  return object.webkitSlice(0, size, type);
}

// most of this is borrowed from lodash.isPlainObject:
// https://github.com/fis-components/lodash.isplainobject/
// blob/29c358140a74f252aeb08c9eb28bef86f2217d4a/index.js

var funcToString = Function.prototype.toString;
var objectCtorString = funcToString.call(Object);

function isPlainObject(value) {
  var proto = Object.getPrototypeOf(value);
  /* istanbul ignore if */
  if (proto === null) { // not sure when this happens, but I guess it can
    return true;
  }
  var Ctor = proto.constructor;
  return (typeof Ctor == 'function' &&
    Ctor instanceof Ctor && funcToString.call(Ctor) == objectCtorString);
}

function clone(object) {
  var newObject;
  var i;
  var len;

  if (!object || typeof object !== 'object') {
    return object;
  }

  if (Array.isArray(object)) {
    newObject = [];
    for (i = 0, len = object.length; i < len; i++) {
      newObject[i] = clone(object[i]);
    }
    return newObject;
  }

  // special case: to avoid inconsistencies between IndexedDB
  // and other backends, we automatically stringify Dates
  if (object instanceof Date) {
    return object.toISOString();
  }

  if (isBinaryObject(object)) {
    return cloneBinaryObject(object);
  }

  if (!isPlainObject(object)) {
    return object; // don't clone objects like Workers
  }

  newObject = {};
  for (i in object) {
    /* istanbul ignore else */
    if (Object.prototype.hasOwnProperty.call(object, i)) {
      var value = clone(object[i]);
      if (typeof value !== 'undefined') {
        newObject[i] = value;
      }
    }
  }
  return newObject;
}

function once(fun) {
  var called = false;
  return getArguments(function (args) {
    /* istanbul ignore if */
    if (called) {
      // this is a smoke test and should never actually happen
      throw new Error('once called more than once');
    } else {
      called = true;
      fun.apply(this, args);
    }
  });
}

function toPromise(func) {
  //create the function we will be returning
  return getArguments(function (args) {
    // Clone arguments
    args = clone(args);
    var self = this;
    var tempCB =
      (typeof args[args.length - 1] === 'function') ? args.pop() : false;
    // if the last argument is a function, assume its a callback
    var usedCB;
    if (tempCB) {
      // if it was a callback, create a new callback which calls it,
      // but do so async so we don't trap any errors
      usedCB = function (err, resp) {
        process.nextTick(function () {
          tempCB(err, resp);
        });
      };
    }
    var promise = new PouchPromise(function (fulfill, reject) {
      var resp;
      try {
        var callback = once(function (err, mesg) {
          if (err) {
            reject(err);
          } else {
            fulfill(mesg);
          }
        });
        // create a callback for this invocation
        // apply the function in the orig context
        args.push(callback);
        resp = func.apply(self, args);
        if (resp && typeof resp.then === 'function') {
          fulfill(resp);
        }
      } catch (e) {
        reject(e);
      }
    });
    // if there is a callback, call it back
    if (usedCB) {
      promise.then(function (result) {
        usedCB(null, result);
      }, usedCB);
    }
    return promise;
  });
}

var log = debug('pouchdb:api');

function adapterFun(name, callback) {
  function logApiCall(self, name, args) {
    /* istanbul ignore if */
    if (log.enabled) {
      var logArgs = [self.name, name];
      for (var i = 0; i < args.length - 1; i++) {
        logArgs.push(args[i]);
      }
      log.apply(null, logArgs);

      // override the callback itself to log the response
      var origCallback = args[args.length - 1];
      args[args.length - 1] = function (err, res) {
        var responseArgs = [self.name, name];
        responseArgs = responseArgs.concat(
          err ? ['error', err] : ['success', res]
        );
        log.apply(null, responseArgs);
        origCallback(err, res);
      };
    }
  }

  return toPromise(getArguments(function (args) {
    if (this._closed) {
      return PouchPromise.reject(new Error('database is closed'));
    }
    if (this._destroyed) {
      return PouchPromise.reject(new Error('database is destroyed'));
    }
    var self = this;
    logApiCall(self, name, args);
    if (!this.taskqueue.isReady) {
      return new PouchPromise(function (fulfill, reject) {
        self.taskqueue.addTask(function (failed) {
          if (failed) {
            reject(failed);
          } else {
            fulfill(self[name].apply(self, args));
          }
        });
      });
    }
    return callback.apply(this, args);
  }));
}

// like underscore/lodash _.pick()
function pick(obj, arr) {
  var res = {};
  for (var i = 0, len = arr.length; i < len; i++) {
    var prop = arr[i];
    if (prop in obj) {
      res[prop] = obj[prop];
    }
  }
  return res;
}

// Most browsers throttle concurrent requests at 6, so it's silly
// to shim _bulk_get by trying to launch potentially hundreds of requests
// and then letting the majority time out. We can handle this ourselves.
var MAX_NUM_CONCURRENT_REQUESTS = 6;

function identityFunction(x) {
  return x;
}

function formatResultForOpenRevsGet(result) {
  return [{
    ok: result
  }];
}

// shim for P/CouchDB adapters that don't directly implement _bulk_get
function bulkGet(db, opts, callback) {
  var requests = opts.docs;

  // consolidate into one request per doc if possible
  var requestsById = {};
  requests.forEach(function (request) {
    if (request.id in requestsById) {
      requestsById[request.id].push(request);
    } else {
      requestsById[request.id] = [request];
    }
  });

  var numDocs = Object.keys(requestsById).length;
  var numDone = 0;
  var perDocResults = new Array(numDocs);

  function collapseResultsAndFinish() {
    var results = [];
    perDocResults.forEach(function (res) {
      res.docs.forEach(function (info) {
        results.push({
          id: res.id,
          docs: [info]
        });
      });
    });
    callback(null, {results: results});
  }

  function checkDone() {
    if (++numDone === numDocs) {
      collapseResultsAndFinish();
    }
  }

  function gotResult(docIndex, id, docs) {
    perDocResults[docIndex] = {id: id, docs: docs};
    checkDone();
  }

  var allRequests = Object.keys(requestsById);

  var i = 0;

  function nextBatch() {

    if (i >= allRequests.length) {
      return;
    }

    var upTo = Math.min(i + MAX_NUM_CONCURRENT_REQUESTS, allRequests.length);
    var batch = allRequests.slice(i, upTo);
    processBatch(batch, i);
    i += batch.length;
  }

  function processBatch(batch, offset) {
    batch.forEach(function (docId, j) {
      var docIdx = offset + j;
      var docRequests = requestsById[docId];

      // just use the first request as the "template"
      // TODO: The _bulk_get API allows for more subtle use cases than this,
      // but for now it is unlikely that there will be a mix of different
      // "atts_since" or "attachments" in the same request, since it's just
      // replicate.js that is using this for the moment.
      // Also, atts_since is aspirational, since we don't support it yet.
      var docOpts = pick(docRequests[0], ['atts_since', 'attachments']);
      docOpts.open_revs = docRequests.map(function (request) {
        // rev is optional, open_revs disallowed
        return request.rev;
      });

      // remove falsey / undefined revisions
      docOpts.open_revs = docOpts.open_revs.filter(identityFunction);

      var formatResult = identityFunction;

      if (docOpts.open_revs.length === 0) {
        delete docOpts.open_revs;

        // when fetching only the "winning" leaf,
        // transform the result so it looks like an open_revs
        // request
        formatResult = formatResultForOpenRevsGet;
      }

      // globally-supplied options
      ['revs', 'attachments', 'binary', 'ajax'].forEach(function (param) {
        if (param in opts) {
          docOpts[param] = opts[param];
        }
      });
      db.get(docId, docOpts, function (err, res) {
        var result;
        /* istanbul ignore if */
        if (err) {
          result = [{error: err}];
        } else {
          result = formatResult(res);
        }
        gotResult(docIdx, docId, result);
        nextBatch();
      });
    });
  }

  nextBatch();

}

function isChromeApp() {
  return (typeof chrome !== "undefined" &&
    typeof chrome.storage !== "undefined" &&
    typeof chrome.storage.local !== "undefined");
}

var hasLocal;

if (isChromeApp()) {
  hasLocal = false;
} else {
  try {
    localStorage.setItem('_pouch_check_localstorage', 1);
    hasLocal = !!localStorage.getItem('_pouch_check_localstorage');
  } catch (e) {
    hasLocal = false;
  }
}

function hasLocalStorage() {
  return hasLocal;
}

inherits(Changes, events.EventEmitter);

/* istanbul ignore next */
function attachBrowserEvents(self) {
  if (isChromeApp()) {
    chrome.storage.onChanged.addListener(function (e) {
      // make sure it's event addressed to us
      if (e.db_name != null) {
        //object only has oldValue, newValue members
        self.emit(e.dbName.newValue);
      }
    });
  } else if (hasLocalStorage()) {
    if (typeof addEventListener !== 'undefined') {
      addEventListener("storage", function (e) {
        self.emit(e.key);
      });
    } else { // old IE
      window.attachEvent("storage", function (e) {
        self.emit(e.key);
      });
    }
  }
}

function Changes() {
  events.EventEmitter.call(this);
  this._listeners = {};

  attachBrowserEvents(this);
}
Changes.prototype.addListener = function (dbName, id, db, opts) {
  /* istanbul ignore if */
  if (this._listeners[id]) {
    return;
  }
  var self = this;
  var inprogress = false;
  function eventFunction() {
    /* istanbul ignore if */
    if (!self._listeners[id]) {
      return;
    }
    if (inprogress) {
      inprogress = 'waiting';
      return;
    }
    inprogress = true;
    var changesOpts = pick(opts, [
      'style', 'include_docs', 'attachments', 'conflicts', 'filter',
      'doc_ids', 'view', 'since', 'query_params', 'binary'
    ]);

    /* istanbul ignore next */
    function onError() {
      inprogress = false;
    }

    db.changes(changesOpts).on('change', function (c) {
      if (c.seq > opts.since && !opts.cancelled) {
        opts.since = c.seq;
        opts.onChange(c);
      }
    }).on('complete', function () {
      if (inprogress === 'waiting') {
        setTimeout(function (){
          eventFunction();
        },0);
      }
      inprogress = false;
    }).on('error', onError);
  }
  this._listeners[id] = eventFunction;
  this.on(dbName, eventFunction);
};

Changes.prototype.removeListener = function (dbName, id) {
  /* istanbul ignore if */
  if (!(id in this._listeners)) {
    return;
  }
  events.EventEmitter.prototype.removeListener.call(this, dbName,
    this._listeners[id]);
  delete this._listeners[id];
};


/* istanbul ignore next */
Changes.prototype.notifyLocalWindows = function (dbName) {
  //do a useless change on a storage thing
  //in order to get other windows's listeners to activate
  if (isChromeApp()) {
    chrome.storage.local.set({dbName: dbName});
  } else if (hasLocalStorage()) {
    localStorage[dbName] = (localStorage[dbName] === "a") ? "b" : "a";
  }
};

Changes.prototype.notify = function (dbName) {
  this.emit(dbName);
  this.notifyLocalWindows(dbName);
};

function guardedConsole(method) {
  /* istanbul ignore else */
  if (console !== 'undefined' && method in console) {
    var args = Array.prototype.slice.call(arguments, 1);
    console[method].apply(console, args);
  }
}

function randomNumber(min, max) {
  var maxTimeout = 600000; // Hard-coded default of 10 minutes
  min = parseInt(min, 10) || 0;
  max = parseInt(max, 10);
  if (max !== max || max <= min) {
    max = (min || 1) << 1; //doubling
  } else {
    max = max + 1;
  }
  // In order to not exceed maxTimeout, pick a random value between half of maxTimeout and maxTimeout
  if(max > maxTimeout) {
    min = maxTimeout >> 1; // divide by two
    max = maxTimeout;
  }
  var ratio = Math.random();
  var range = max - min;

  return ~~(range * ratio + min); // ~~ coerces to an int, but fast.
}

function defaultBackOff(min) {
  var max = 0;
  if (!min) {
    max = 2000;
  }
  return randomNumber(min, max);
}

// designed to give info to browser users, who are disturbed
// when they see http errors in the console
function explainError(status, str) {
  guardedConsole('info', 'The above ' + status + ' is totally normal. ' + str);
}

// forked from
// https://github.com/vmattos/js-extend/blob/7023fd69a9e9552688086b8b8006b1fcf916a306/extend.js
// TODO: I don't know why we have two different extend() functions in PouchDB

var slice = Array.prototype.slice;
var each = Array.prototype.forEach;

function extend$1(obj) {
  if (typeof obj !== 'object') {
    throw obj + ' is not an object' ;
  }

  var sources = slice.call(arguments, 1);

  each.call(sources, function (source) {
    if (source) {
      for (var prop in source) {
        if (typeof source[prop] === 'object' && obj[prop]) {
          extend$1.call(obj, obj[prop], source[prop]);
        } else {
          obj[prop] = source[prop];
        }
      }
    }
  });

  return obj;
}

inherits(PouchError, Error);

function PouchError(opts) {
  Error.call(this, opts.reason);
  this.status = opts.status;
  this.name = opts.error;
  this.message = opts.reason;
  this.error = true;
}

PouchError.prototype.toString = function () {
  return JSON.stringify({
    status: this.status,
    name: this.name,
    message: this.message,
    reason: this.reason
  });
};

var UNAUTHORIZED = new PouchError({
  status: 401,
  error: 'unauthorized',
  reason: "Name or password is incorrect."
});

var MISSING_BULK_DOCS = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: "Missing JSON list of 'docs'"
});

var MISSING_DOC = new PouchError({
  status: 404,
  error: 'not_found',
  reason: 'missing'
});

var REV_CONFLICT = new PouchError({
  status: 409,
  error: 'conflict',
  reason: 'Document update conflict'
});

var INVALID_ID = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: '_id field must contain a string'
});

var MISSING_ID = new PouchError({
  status: 412,
  error: 'missing_id',
  reason: '_id is required for puts'
});

var RESERVED_ID = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: 'Only reserved document ids may start with underscore.'
});

var NOT_OPEN = new PouchError({
  status: 412,
  error: 'precondition_failed',
  reason: 'Database not open'
});

var UNKNOWN_ERROR = new PouchError({
  status: 500,
  error: 'unknown_error',
  reason: 'Database encountered an unknown error'
});

var BAD_ARG = new PouchError({
  status: 500,
  error: 'badarg',
  reason: 'Some query argument is invalid'
});

var INVALID_REQUEST = new PouchError({
  status: 400,
  error: 'invalid_request',
  reason: 'Request was invalid'
});

var QUERY_PARSE_ERROR = new PouchError({
  status: 400,
  error: 'query_parse_error',
  reason: 'Some query parameter is invalid'
});

var DOC_VALIDATION = new PouchError({
  status: 500,
  error: 'doc_validation',
  reason: 'Bad special document member'
});

var BAD_REQUEST = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: 'Something wrong with the request'
});

var NOT_AN_OBJECT = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: 'Document must be a JSON object'
});

var DB_MISSING = new PouchError({
  status: 404,
  error: 'not_found',
  reason: 'Database not found'
});

var IDB_ERROR = new PouchError({
  status: 500,
  error: 'indexed_db_went_bad',
  reason: 'unknown'
});

var WSQ_ERROR = new PouchError({
  status: 500,
  error: 'web_sql_went_bad',
  reason: 'unknown'
});

var LDB_ERROR = new PouchError({
  status: 500,
  error: 'levelDB_went_went_bad',
  reason: 'unknown'
});

var FORBIDDEN = new PouchError({
  status: 403,
  error: 'forbidden',
  reason: 'Forbidden by design doc validate_doc_update function'
});

var INVALID_REV = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: 'Invalid rev format'
});

var FILE_EXISTS = new PouchError({
  status: 412,
  error: 'file_exists',
  reason: 'The database could not be created, the file already exists.'
});

var MISSING_STUB = new PouchError({
  status: 412,
  error: 'missing_stub'
});

var INVALID_URL = new PouchError({
  status: 413,
  error: 'invalid_url',
  reason: 'Provided URL is invalid'
});

function createError(error, reason) {
  function CustomPouchError(reason) {
    // inherit error properties from our parent error manually
    // so as to allow proper JSON parsing.
    /* jshint ignore:start */
    for (var p in error) {
      if (typeof error[p] !== 'function') {
        this[p] = error[p];
      }
    }
    /* jshint ignore:end */
    if (reason !== undefined) {
      this.reason = reason;
    }
  }
  CustomPouchError.prototype = PouchError.prototype;
  return new CustomPouchError(reason);
}

function generateErrorFromResponse(err) {

  if (typeof err !== 'object') {
    var data = err;
    err = UNKNOWN_ERROR;
    err.data = data;
  }

  if ('error' in err && err.error === 'conflict') {
    err.name = 'conflict';
    err.status = 409;
  }

  if (!('name' in err)) {
    err.name = err.error || 'unknown';
  }

  if (!('status' in err)) {
    err.status = 500;
  }

  if (!('message' in err)) {
    err.message = err.message || err.reason;
  }

  return err;
}

function tryFilter(filter, doc, req) {
  try {
    return !filter(doc, req);
  } catch (err) {
    var msg = 'Filter function threw: ' + err.toString();
    return createError(BAD_REQUEST, msg);
  }
}

function filterChange(opts) {
  var req = {};
  var hasFilter = opts.filter && typeof opts.filter === 'function';
  req.query = opts.query_params;

  return function filter(change) {
    if (!change.doc) {
      // CSG sends events on the changes feed that don't have documents,
      // this hack makes a whole lot of existing code robust.
      change.doc = {};
    }

    var filterReturn = hasFilter && tryFilter(opts.filter, change.doc, req);

    if (typeof filterReturn === 'object') {
      return filterReturn;
    }

    if (filterReturn) {
      return false;
    }

    if (!opts.include_docs) {
      delete change.doc;
    } else if (!opts.attachments) {
      for (var att in change.doc._attachments) {
        /* istanbul ignore else */
        if (change.doc._attachments.hasOwnProperty(att)) {
          change.doc._attachments[att].stub = true;
        }
      }
    }
    return true;
  };
}

function flatten(arrs) {
  var res = [];
  for (var i = 0, len = arrs.length; i < len; i++) {
    res = res.concat(arrs[i]);
  }
  return res;
}

// Determine id an ID is valid
//   - invalid IDs begin with an underescore that does not begin '_design' or
//     '_local'
//   - any other string value is a valid id
// Returns the specific error object for each case
function invalidIdError(id) {
  var err;
  if (!id) {
    err = createError(MISSING_ID);
  } else if (typeof id !== 'string') {
    err = createError(INVALID_ID);
  } else if (/^_/.test(id) && !(/^_(design|local)/).test(id)) {
    err = createError(RESERVED_ID);
  }
  if (err) {
    throw err;
  }
}

function listenerCount(ee, type) {
  return 'listenerCount' in ee ? ee.listenerCount(type) :
                                 events.EventEmitter.listenerCount(ee, type);
}

function parseDesignDocFunctionName(s) {
  if (!s) {
    return null;
  }
  var parts = s.split('/');
  if (parts.length === 2) {
    return parts;
  }
  if (parts.length === 1) {
    return [s, s];
  }
  return null;
}

function normalizeDesignDocFunctionName(s) {
  var normalized = parseDesignDocFunctionName(s);
  return normalized ? normalized.join('/') : null;
}

// originally parseUri 1.2.2, now patched by us
// (c) Steven Levithan <stevenlevithan.com>
// MIT License
var keys = ["source", "protocol", "authority", "userInfo", "user", "password",
    "host", "port", "relative", "path", "directory", "file", "query", "anchor"];
var qName ="queryKey";
var qParser = /(?:^|&)([^&=]*)=?([^&]*)/g;

// use the "loose" parser
/* jshint maxlen: false */
var parser = /^(?:(?![^:@]+:[^:@\/]*@)([^:\/?#.]+):)?(?:\/\/)?((?:(([^:@]*)(?::([^:@]*))?)?@)?([^:\/?#]*)(?::(\d*))?)(((\/(?:[^?#](?![^?#\/]*\.[^?#\/.]+(?:[?#]|$)))*\/?)?([^?#\/]*))(?:\?([^#]*))?(?:#(.*))?)/;

function parseUri(str) {
  var m = parser.exec(str);
  var uri = {};
  var i = 14;

  while (i--) {
    var key = keys[i];
    var value = m[i] || "";
    var encoded = ['user', 'password'].indexOf(key) !== -1;
    uri[key] = encoded ? decodeURIComponent(value) : value;
  }

  uri[qName] = {};
  uri[keys[12]].replace(qParser, function ($0, $1, $2) {
    if ($1) {
      uri[qName][$1] = $2;
    }
  });

  return uri;
}

// this is essentially the "update sugar" function from daleharvey/pouchdb#1388
// the diffFun tells us what delta to apply to the doc.  it either returns
// the doc, or false if it doesn't need to do an update after all
function upsert(db, docId, diffFun) {
  return new PouchPromise(function (fulfill, reject) {
    db.get(docId, function (err, doc) {
      if (err) {
        /* istanbul ignore next */
        if (err.status !== 404) {
          return reject(err);
        }
        doc = {};
      }

      // the user might change the _rev, so save it for posterity
      var docRev = doc._rev;
      var newDoc = diffFun(doc);

      if (!newDoc) {
        // if the diffFun returns falsy, we short-circuit as
        // an optimization
        return fulfill({updated: false, rev: docRev});
      }

      // users aren't allowed to modify these values,
      // so reset them here
      newDoc._id = docId;
      newDoc._rev = docRev;
      fulfill(tryAndPut(db, newDoc, diffFun));
    });
  });
}

function tryAndPut(db, doc, diffFun) {
  return db.put(doc).then(function (res) {
    return {
      updated: true,
      rev: res.rev
    };
  }, function (err) {
    /* istanbul ignore next */
    if (err.status !== 409) {
      throw err;
    }
    return upsert(db, doc._id, diffFun);
  });
}

// BEGIN Math.uuid.js

/*!
Math.uuid.js (v1.4)
http://www.broofa.com
mailto:robert@broofa.com

Copyright (c) 2010 Robert Kieffer
Dual licensed under the MIT and GPL licenses.
*/

/*
 * Generate a random uuid.
 *
 * USAGE: Math.uuid(length, radix)
 *   length - the desired number of characters
 *   radix  - the number of allowable values for each character.
 *
 * EXAMPLES:
 *   // No arguments  - returns RFC4122, version 4 ID
 *   >>> Math.uuid()
 *   "92329D39-6F5C-4520-ABFC-AAB64544E172"
 *
 *   // One argument - returns ID of the specified length
 *   >>> Math.uuid(15)     // 15 character ID (default base=62)
 *   "VcydxgltxrVZSTV"
 *
 *   // Two arguments - returns ID of the specified length, and radix. 
 *   // (Radix must be <= 62)
 *   >>> Math.uuid(8, 2)  // 8 character ID (base=2)
 *   "01001010"
 *   >>> Math.uuid(8, 10) // 8 character ID (base=10)
 *   "47473046"
 *   >>> Math.uuid(8, 16) // 8 character ID (base=16)
 *   "098F4D35"
 */
var chars = (
  '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ' +
  'abcdefghijklmnopqrstuvwxyz'
).split('');
function getValue(radix) {
  return 0 | Math.random() * radix;
}
function uuid(len, radix) {
  radix = radix || chars.length;
  var out = '';
  var i = -1;

  if (len) {
    // Compact form
    while (++i < len) {
      out += chars[getValue(radix)];
    }
    return out;
  }
    // rfc4122, version 4 form
    // Fill in random data.  At i==19 set the high bits of clock sequence as
    // per rfc4122, sec. 4.1.5
  while (++i < 36) {
    switch (i) {
      case 8:
      case 13:
      case 18:
      case 23:
        out += '-';
        break;
      case 19:
        out += chars[(getValue(16) & 0x3) | 0x8];
        break;
      default:
        out += chars[getValue(16)];
    }
  }

  return out;
}

// based on https://github.com/montagejs/collections
function mangle(key) {
  return '$' + key;
}
function unmangle(key) {
  return key.substring(1);
}
function _Map() {
  this.store = {};
}
_Map.prototype.get = function (key) {
  var mangled = mangle(key);
  return this.store[mangled];
};
_Map.prototype.set = function (key, value) {
  var mangled = mangle(key);
  this.store[mangled] = value;
  return true;
};
_Map.prototype.has = function (key) {
  var mangled = mangle(key);
  return mangled in this.store;
};
_Map.prototype.delete = function (key) {
  var mangled = mangle(key);
  var res = mangled in this.store;
  delete this.store[mangled];
  return res;
};
_Map.prototype.forEach = function (cb) {
  var keys = Object.keys(this.store);
  for (var i = 0, len = keys.length; i < len; i++) {
    var key = keys[i];
    var value = this.store[key];
    key = unmangle(key);
    cb(value, key);
  }
};

function _Set(array) {
  this.store = new _Map();

  // init with an array
  if (array && Array.isArray(array)) {
    for (var i = 0, len = array.length; i < len; i++) {
      this.add(array[i]);
    }
  }
}
_Set.prototype.add = function (key) {
  return this.store.set(key, true);
};
_Set.prototype.has = function (key) {
  return this.store.has(key);
};

// We fetch all leafs of the revision tree, and sort them based on tree length
// and whether they were deleted, undeleted documents with the longest revision
// tree (most edits) win
// The final sort algorithm is slightly documented in a sidebar here:
// http://guide.couchdb.org/draft/conflicts.html
function winningRev(metadata) {
  var winningId;
  var winningPos;
  var winningDeleted;
  var toVisit = metadata.rev_tree.slice();
  var node;
  while ((node = toVisit.pop())) {
    var tree = node.ids;
    var branches = tree[2];
    var pos = node.pos;
    if (branches.length) { // non-leaf
      for (var i = 0, len = branches.length; i < len; i++) {
        toVisit.push({pos: pos + 1, ids: branches[i]});
      }
      continue;
    }
    var deleted = !!tree[1].deleted;
    var id = tree[0];
    // sort by deleted, then pos, then id
    if (!winningId || (winningDeleted !== deleted ? winningDeleted :
        winningPos !== pos ? winningPos < pos : winningId < id)) {
      winningId = id;
      winningPos = pos;
      winningDeleted = deleted;
    }
  }

  return winningPos + '-' + winningId;
}

// Pretty much all below can be combined into a higher order function to
// traverse revisions
// The return value from the callback will be passed as context to all
// children of that node
function traverseRevTree(revs, callback) {
  var toVisit = revs.slice();

  var node;
  while ((node = toVisit.pop())) {
    var pos = node.pos;
    var tree = node.ids;
    var branches = tree[2];
    var newCtx =
      callback(branches.length === 0, pos, tree[0], node.ctx, tree[1]);
    for (var i = 0, len = branches.length; i < len; i++) {
      toVisit.push({pos: pos + 1, ids: branches[i], ctx: newCtx});
    }
  }
}

function sortByPos(a, b) {
  return a.pos - b.pos;
}

function collectLeaves(revs) {
  var leaves = [];
  traverseRevTree(revs, function (isLeaf, pos, id, acc, opts) {
    if (isLeaf) {
      leaves.push({rev: pos + "-" + id, pos: pos, opts: opts});
    }
  });
  leaves.sort(sortByPos).reverse();
  for (var i = 0, len = leaves.length; i < len; i++) {
    delete leaves[i].pos;
  }
  return leaves;
}

// returns revs of all conflicts that is leaves such that
// 1. are not deleted and
// 2. are different than winning revision
function collectConflicts(metadata) {
  var win = winningRev(metadata);
  var leaves = collectLeaves(metadata.rev_tree);
  var conflicts = [];
  for (var i = 0, len = leaves.length; i < len; i++) {
    var leaf = leaves[i];
    if (leaf.rev !== win && !leaf.opts.deleted) {
      conflicts.push(leaf.rev);
    }
  }
  return conflicts;
}

// compact a tree by marking its non-leafs as missing,
// and return a list of revs to delete
function compactTree(metadata) {
  var revs = [];
  traverseRevTree(metadata.rev_tree, function (isLeaf, pos,
                                               revHash, ctx, opts) {
    if (opts.status === 'available' && !isLeaf) {
      revs.push(pos + '-' + revHash);
      opts.status = 'missing';
    }
  });
  return revs;
}

// build up a list of all the paths to the leafs in this revision tree
function rootToLeaf(revs) {
  var paths = [];
  var toVisit = revs.slice();
  var node;
  while ((node = toVisit.pop())) {
    var pos = node.pos;
    var tree = node.ids;
    var id = tree[0];
    var opts = tree[1];
    var branches = tree[2];
    var isLeaf = branches.length === 0;

    var history = node.history ? node.history.slice() : [];
    history.push({id: id, opts: opts});
    if (isLeaf) {
      paths.push({pos: (pos + 1 - history.length), ids: history});
    }
    for (var i = 0, len = branches.length; i < len; i++) {
      toVisit.push({pos: pos + 1, ids: branches[i], history: history});
    }
  }
  return paths.reverse();
}

// for a better overview of what this is doing, read:
// https://github.com/apache/couchdb-couch/blob/master/src/couch_key_tree.erl
//
// But for a quick intro, CouchDB uses a revision tree to store a documents
// history, A -> B -> C, when a document has conflicts, that is a branch in the
// tree, A -> (B1 | B2 -> C), We store these as a nested array in the format
//
// KeyTree = [Path ... ]
// Path = {pos: position_from_root, ids: Tree}
// Tree = [Key, Opts, [Tree, ...]], in particular single node: [Key, []]

function sortByPos$1(a, b) {
  return a.pos - b.pos;
}

// classic binary search
function binarySearch(arr, item, comparator) {
  var low = 0;
  var high = arr.length;
  var mid;
  while (low < high) {
    mid = (low + high) >>> 1;
    if (comparator(arr[mid], item) < 0) {
      low = mid + 1;
    } else {
      high = mid;
    }
  }
  return low;
}

// assuming the arr is sorted, insert the item in the proper place
function insertSorted(arr, item, comparator) {
  var idx = binarySearch(arr, item, comparator);
  arr.splice(idx, 0, item);
}

// Turn a path as a flat array into a tree with a single branch.
// If any should be stemmed from the beginning of the array, that's passed
// in as the second argument
function pathToTree(path, numStemmed) {
  var root;
  var leaf;
  for (var i = numStemmed, len = path.length; i < len; i++) {
    var node = path[i];
    var currentLeaf = [node.id, node.opts, []];
    if (leaf) {
      leaf[2].push(currentLeaf);
      leaf = currentLeaf;
    } else {
      root = leaf = currentLeaf;
    }
  }
  return root;
}

// compare the IDs of two trees
function compareTree(a, b) {
  return a[0] < b[0] ? -1 : 1;
}

// Merge two trees together
// The roots of tree1 and tree2 must be the same revision
function mergeTree(in_tree1, in_tree2) {
  var queue = [{tree1: in_tree1, tree2: in_tree2}];
  var conflicts = false;
  while (queue.length > 0) {
    var item = queue.pop();
    var tree1 = item.tree1;
    var tree2 = item.tree2;

    if (tree1[1].status || tree2[1].status) {
      tree1[1].status =
        (tree1[1].status ===  'available' ||
        tree2[1].status === 'available') ? 'available' : 'missing';
    }

    for (var i = 0; i < tree2[2].length; i++) {
      if (!tree1[2][0]) {
        conflicts = 'new_leaf';
        tree1[2][0] = tree2[2][i];
        continue;
      }

      var merged = false;
      for (var j = 0; j < tree1[2].length; j++) {
        if (tree1[2][j][0] === tree2[2][i][0]) {
          queue.push({tree1: tree1[2][j], tree2: tree2[2][i]});
          merged = true;
        }
      }
      if (!merged) {
        conflicts = 'new_branch';
        insertSorted(tree1[2], tree2[2][i], compareTree);
      }
    }
  }
  return {conflicts: conflicts, tree: in_tree1};
}

function doMerge(tree, path, dontExpand) {
  var restree = [];
  var conflicts = false;
  var merged = false;
  var res;

  if (!tree.length) {
    return {tree: [path], conflicts: 'new_leaf'};
  }

  for (var i = 0, len = tree.length; i < len; i++) {
    var branch = tree[i];
    if (branch.pos === path.pos && branch.ids[0] === path.ids[0]) {
      // Paths start at the same position and have the same root, so they need
      // merged
      res = mergeTree(branch.ids, path.ids);
      restree.push({pos: branch.pos, ids: res.tree});
      conflicts = conflicts || res.conflicts;
      merged = true;
    } else if (dontExpand !== true) {
      // The paths start at a different position, take the earliest path and
      // traverse up until it as at the same point from root as the path we
      // want to merge.  If the keys match we return the longer path with the
      // other merged After stemming we dont want to expand the trees

      var t1 = branch.pos < path.pos ? branch : path;
      var t2 = branch.pos < path.pos ? path : branch;
      var diff = t2.pos - t1.pos;

      var candidateParents = [];

      var trees = [];
      trees.push({ids: t1.ids, diff: diff, parent: null, parentIdx: null});
      while (trees.length > 0) {
        var item = trees.pop();
        if (item.diff === 0) {
          if (item.ids[0] === t2.ids[0]) {
            candidateParents.push(item);
          }
          continue;
        }
        var elements = item.ids[2];
        for (var j = 0, elementsLen = elements.length; j < elementsLen; j++) {
          trees.push({
            ids: elements[j],
            diff: item.diff - 1,
            parent: item.ids,
            parentIdx: j
          });
        }
      }

      var el = candidateParents[0];

      if (!el) {
        restree.push(branch);
      } else {
        res = mergeTree(el.ids, t2.ids);
        el.parent[2][el.parentIdx] = res.tree;
        restree.push({pos: t1.pos, ids: t1.ids});
        conflicts = conflicts || res.conflicts;
        merged = true;
      }
    } else {
      restree.push(branch);
    }
  }

  // We didnt find
  if (!merged) {
    restree.push(path);
  }

  restree.sort(sortByPos$1);

  return {
    tree: restree,
    conflicts: conflicts || 'internal_node'
  };
}

// To ensure we dont grow the revision tree infinitely, we stem old revisions
function stem(tree, depth) {
  // First we break out the tree into a complete list of root to leaf paths
  var paths = rootToLeaf(tree);
  var maybeStem = {};

  var result;
  for (var i = 0, len = paths.length; i < len; i++) {
    // Then for each path, we cut off the start of the path based on the
    // `depth` to stem to, and generate a new set of flat trees
    var path = paths[i];
    var stemmed = path.ids;
    var numStemmed = Math.max(0, stemmed.length - depth);
    var stemmedNode = {
      pos: path.pos + numStemmed,
      ids: pathToTree(stemmed, numStemmed)
    };

    for (var s = 0; s < numStemmed; s++) {
      var rev = (path.pos + s) + '-' + stemmed[s].id;
      maybeStem[rev] = true;
    }

    // Then we remerge all those flat trees together, ensuring that we dont
    // connect trees that would go beyond the depth limit
    if (result) {
      result = doMerge(result, stemmedNode, true).tree;
    } else {
      result = [stemmedNode];
    }
  }

  traverseRevTree(result, function (isLeaf, pos, revHash) {
    // some revisions may have been removed in a branch but not in another
    delete maybeStem[pos + '-' + revHash];
  });

  return {
    tree: result,
    revs: Object.keys(maybeStem)
  };
}

function merge(tree, path, depth) {
  var newTree = doMerge(tree, path);
  var stemmed = stem(newTree.tree, depth);
  return {
    tree: stemmed.tree,
    stemmedRevs: stemmed.revs,
    conflicts: newTree.conflicts
  };
}

// return true if a rev exists in the rev tree, false otherwise
function revExists(revs, rev) {
  var toVisit = revs.slice();
  var splitRev = rev.split('-');
  var targetPos = parseInt(splitRev[0], 10);
  var targetId = splitRev[1];

  var node;
  while ((node = toVisit.pop())) {
    if (node.pos === targetPos && node.ids[0] === targetId) {
      return true;
    }
    var branches = node.ids[2];
    for (var i = 0, len = branches.length; i < len; i++) {
      toVisit.push({pos: node.pos + 1, ids: branches[i]});
    }
  }
  return false;
}

function getTrees(node) {
  return node.ids;
}

// check if a specific revision of a doc has been deleted
//  - metadata: the metadata object from the doc store
//  - rev: (optional) the revision to check. defaults to winning revision
function isDeleted(metadata, rev) {
  if (!rev) {
    rev = winningRev(metadata);
  }
  var id = rev.substring(rev.indexOf('-') + 1);
  var toVisit = metadata.rev_tree.map(getTrees);

  var tree;
  while ((tree = toVisit.pop())) {
    if (tree[0] === id) {
      return !!tree[1].deleted;
    }
    toVisit = toVisit.concat(tree[2]);
  }
}

function isLocalId(id) {
  return (/^_local/).test(id);
}

function evalFilter(input) {
  return scopedEval('"use strict";\nreturn ' + input + ';', {});
}

function evalView(input) {
  var code = [
    'return function(doc) {',
    '  "use strict";',
    '  var emitted = false;',
    '  var emit = function (a, b) {',
    '    emitted = true;',
    '  };',
    '  var view = ' + input + ';',
    '  view(doc);',
    '  if (emitted) {',
    '    return true;',
    '  }',
    '};'
  ].join('\n');

  return scopedEval(code, {});
}

inherits(Changes$1, events.EventEmitter);

function tryCatchInChangeListener(self, change) {
  // isolate try/catches to avoid V8 deoptimizations
  try {
    self.emit('change', change);
  } catch (e) {
    guardedConsole('error', 'Error in .on("change", function):', e);
  }
}

function Changes$1(db, opts, callback) {
  events.EventEmitter.call(this);
  var self = this;
  this.db = db;
  opts = opts ? clone(opts) : {};
  var complete = opts.complete = once(function (err, resp) {
    if (err) {
      if (listenerCount(self, 'error') > 0) {
        self.emit('error', err);
      }
    } else {
      self.emit('complete', resp);
    }
    self.removeAllListeners();
    db.removeListener('destroyed', onDestroy);
  });
  if (callback) {
    self.on('complete', function (resp) {
      callback(null, resp);
    });
    self.on('error', callback);
  }
  function onDestroy() {
    self.cancel();
  }
  db.once('destroyed', onDestroy);

  opts.onChange = function (change) {
    /* istanbul ignore if */
    if (opts.isCancelled) {
      return;
    }
    tryCatchInChangeListener(self, change);
  };

  var promise = new PouchPromise(function (fulfill, reject) {
    opts.complete = function (err, res) {
      if (err) {
        reject(err);
      } else {
        fulfill(res);
      }
    };
  });
  self.once('cancel', function () {
    db.removeListener('destroyed', onDestroy);
    opts.complete(null, {status: 'cancelled'});
  });
  this.then = promise.then.bind(promise);
  this['catch'] = promise['catch'].bind(promise);
  this.then(function (result) {
    complete(null, result);
  }, complete);



  if (!db.taskqueue.isReady) {
    db.taskqueue.addTask(function (failed) {
      if (failed) {
        opts.complete(failed);
      } else if (self.isCancelled) {
        self.emit('cancel');
      } else {
        self.doChanges(opts);
      }
    });
  } else {
    self.doChanges(opts);
  }
}
Changes$1.prototype.cancel = function () {
  this.isCancelled = true;
  if (this.db.taskqueue.isReady) {
    this.emit('cancel');
  }
};
function processChange(doc, metadata, opts) {
  var changeList = [{rev: doc._rev}];
  if (opts.style === 'all_docs') {
    changeList = collectLeaves(metadata.rev_tree)
    .map(function (x) { return {rev: x.rev}; });
  }
  var change = {
    id: metadata.id,
    changes: changeList,
    doc: doc
  };

  if (isDeleted(metadata, doc._rev)) {
    change.deleted = true;
  }
  if (opts.conflicts) {
    change.doc._conflicts = collectConflicts(metadata);
    if (!change.doc._conflicts.length) {
      delete change.doc._conflicts;
    }
  }
  return change;
}

Changes$1.prototype.doChanges = function (opts) {
  var self = this;
  var callback = opts.complete;

  opts = clone(opts);
  if ('live' in opts && !('continuous' in opts)) {
    opts.continuous = opts.live;
  }
  opts.processChange = processChange;

  if (opts.since === 'latest') {
    opts.since = 'now';
  }
  if (!opts.since) {
    opts.since = 0;
  }
  if (opts.since === 'now') {
    this.db.info().then(function (info) {
      /* istanbul ignore if */
      if (self.isCancelled) {
        callback(null, {status: 'cancelled'});
        return;
      }
      opts.since = info.update_seq;
      self.doChanges(opts);
    }, callback);
    return;
  }


  if (opts.view && !opts.filter) {
    opts.filter = '_view';
  }

  if (opts.filter && typeof opts.filter === 'string') {
    if (opts.filter === '_view') {
      opts.view = normalizeDesignDocFunctionName(opts.view);
    } else {
      opts.filter = normalizeDesignDocFunctionName(opts.filter);
    }

    if (this.db.type() !== 'http' && !opts.doc_ids) {
      return this.filterChanges(opts);
    }
  }

  if (!('descending' in opts)) {
    opts.descending = false;
  }

  // 0 and 1 should return 1 document
  opts.limit = opts.limit === 0 ? 1 : opts.limit;
  opts.complete = callback;
  var newPromise = this.db._changes(opts);
  /* istanbul ignore else */
  if (newPromise && typeof newPromise.cancel === 'function') {
    var cancel = self.cancel;
    self.cancel = getArguments(function (args) {
      newPromise.cancel();
      cancel.apply(this, args);
    });
  }
};

Changes$1.prototype.filterChanges = function (opts) {
  var self = this;
  var callback = opts.complete;
  if (opts.filter === '_view') {
    if (!opts.view || typeof opts.view !== 'string') {
      var err = createError(BAD_REQUEST,
        '`view` filter parameter not found or invalid.');
      return callback(err);
    }
    // fetch a view from a design doc, make it behave like a filter
    var viewName = parseDesignDocFunctionName(opts.view);
    this.db.get('_design/' + viewName[0], function (err, ddoc) {
      /* istanbul ignore if */
      if (self.isCancelled) {
        return callback(null, {status: 'cancelled'});
      }
      /* istanbul ignore next */
      if (err) {
        return callback(generateErrorFromResponse(err));
      }
      var mapFun = ddoc && ddoc.views && ddoc.views[viewName[1]] &&
        ddoc.views[viewName[1]].map;
      if (!mapFun) {
        return callback(createError(MISSING_DOC,
          (ddoc.views ? 'missing json key: ' + viewName[1] :
            'missing json key: views')));
      }
      opts.filter = evalView(mapFun);
      self.doChanges(opts);
    });
  } else {
    // fetch a filter from a design doc
    var filterName = parseDesignDocFunctionName(opts.filter);
    if (!filterName) {
      return self.doChanges(opts);
    }
    this.db.get('_design/' + filterName[0], function (err, ddoc) {
      /* istanbul ignore if */
      if (self.isCancelled) {
        return callback(null, {status: 'cancelled'});
      }
      /* istanbul ignore next */
      if (err) {
        return callback(generateErrorFromResponse(err));
      }
      var filterFun = ddoc && ddoc.filters && ddoc.filters[filterName[1]];
      if (!filterFun) {
        return callback(createError(MISSING_DOC,
          ((ddoc && ddoc.filters) ? 'missing json key: ' + filterName[1]
            : 'missing json key: filters')));
      }
      opts.filter = evalFilter(filterFun);
      self.doChanges(opts);
    });
  }
};

/*
 * A generic pouch adapter
 */

function compare(left, right) {
  return left < right ? -1 : left > right ? 1 : 0;
}

// returns first element of arr satisfying callback predicate
function arrayFirst(arr, callback) {
  for (var i = 0; i < arr.length; i++) {
    if (callback(arr[i], i) === true) {
      return arr[i];
    }
  }
}

// Wrapper for functions that call the bulkdocs api with a single doc,
// if the first result is an error, return an error
function yankError(callback) {
  return function (err, results) {
    if (err || (results[0] && results[0].error)) {
      callback(err || results[0]);
    } else {
      callback(null, results.length ? results[0]  : results);
    }
  };
}

// clean docs given to us by the user
function cleanDocs(docs) {
  for (var i = 0; i < docs.length; i++) {
    var doc = docs[i];
    if (doc._deleted) {
      delete doc._attachments; // ignore atts for deleted docs
    } else if (doc._attachments) {
      // filter out extraneous keys from _attachments
      var atts = Object.keys(doc._attachments);
      for (var j = 0; j < atts.length; j++) {
        var att = atts[j];
        doc._attachments[att] = pick(doc._attachments[att],
          ['data', 'digest', 'content_type', 'length', 'revpos', 'stub']);
      }
    }
  }
}

// compare two docs, first by _id then by _rev
function compareByIdThenRev(a, b) {
  var idCompare = compare(a._id, b._id);
  if (idCompare !== 0) {
    return idCompare;
  }
  var aStart = a._revisions ? a._revisions.start : 0;
  var bStart = b._revisions ? b._revisions.start : 0;
  return compare(aStart, bStart);
}

// for every node in a revision tree computes its distance from the closest
// leaf
function computeHeight(revs) {
  var height = {};
  var edges = [];
  traverseRevTree(revs, function (isLeaf, pos, id, prnt) {
    var rev = pos + "-" + id;
    if (isLeaf) {
      height[rev] = 0;
    }
    if (prnt !== undefined) {
      edges.push({from: prnt, to: rev});
    }
    return rev;
  });

  edges.reverse();
  edges.forEach(function (edge) {
    if (height[edge.from] === undefined) {
      height[edge.from] = 1 + height[edge.to];
    } else {
      height[edge.from] = Math.min(height[edge.from], 1 + height[edge.to]);
    }
  });
  return height;
}

function allDocsKeysQuery(api, opts, callback) {
  var keys =  ('limit' in opts) ?
      opts.keys.slice(opts.skip, opts.limit + opts.skip) :
      (opts.skip > 0) ? opts.keys.slice(opts.skip) : opts.keys;
  if (opts.descending) {
    keys.reverse();
  }
  if (!keys.length) {
    return api._allDocs({limit: 0}, callback);
  }
  var finalResults = {
    offset: opts.skip
  };
  return PouchPromise.all(keys.map(function (key) {
    var subOpts = extend$1({key: key, deleted: 'ok'}, opts);
    ['limit', 'skip', 'keys'].forEach(function (optKey) {
      delete subOpts[optKey];
    });
    return new PouchPromise(function (resolve, reject) {
      api._allDocs(subOpts, function (err, res) {
        /* istanbul ignore if */
        if (err) {
          return reject(err);
        }
        finalResults.total_rows = res.total_rows;
        resolve(res.rows[0] || {key: key, error: 'not_found'});
      });
    });
  })).then(function (results) {
    finalResults.rows = results;
    return finalResults;
  });
}

// all compaction is done in a queue, to avoid attaching
// too many listeners at once
function doNextCompaction(self) {
  var task = self._compactionQueue[0];
  var opts = task.opts;
  var callback = task.callback;
  self.get('_local/compaction').catch(function () {
    return false;
  }).then(function (doc) {
    if (doc && doc.last_seq) {
      opts.last_seq = doc.last_seq;
    }
    self._compact(opts, function (err, res) {
      /* istanbul ignore if */
      if (err) {
        callback(err);
      } else {
        callback(null, res);
      }
      process.nextTick(function () {
        self._compactionQueue.shift();
        if (self._compactionQueue.length) {
          doNextCompaction(self);
        }
      });
    });
  });
}

function attachmentNameError(name) {
  if (name.charAt(0) === '_') {
    return name + 'is not a valid attachment name, attachment ' +
      'names cannot start with \'_\'';
  }
  return false;
}

inherits(AbstractPouchDB, events.EventEmitter);

function AbstractPouchDB() {
  events.EventEmitter.call(this);
}

AbstractPouchDB.prototype.post =
  adapterFun('post', function (doc, opts, callback) {
  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }
  if (typeof doc !== 'object' || Array.isArray(doc)) {
    return callback(createError(NOT_AN_OBJECT));
  }
  this.bulkDocs({docs: [doc]}, opts, yankError(callback));
});

AbstractPouchDB.prototype.put = adapterFun('put', function (doc, opts, cb) {
  if (typeof opts === 'function') {
    cb = opts;
    opts = {};
  }
  if (typeof doc !== 'object' || Array.isArray(doc)) {
    return cb(createError(NOT_AN_OBJECT));
  }
  invalidIdError(doc._id);
  if (isLocalId(doc._id) && typeof this._putLocal === 'function') {
    if (doc._deleted) {
      return this._removeLocal(doc, cb);
    } else {
      return this._putLocal(doc, cb);
    }
  }
  if (typeof this._put === 'function' && opts.new_edits !== false) {
    this._put(doc, opts, cb);
  } else {
    this.bulkDocs({docs: [doc]}, opts, yankError(cb));
  }
});

AbstractPouchDB.prototype.putAttachment =
  adapterFun('putAttachment', function (docId, attachmentId, rev,
                                              blob, type) {
  var api = this;
  if (typeof type === 'function') {
    type = blob;
    blob = rev;
    rev = null;
  }
  // Lets fix in https://github.com/pouchdb/pouchdb/issues/3267
  /* istanbul ignore if */
  if (typeof type === 'undefined') {
    type = blob;
    blob = rev;
    rev = null;
  }

  function createAttachment(doc) {
    var prevrevpos = '_rev' in doc ? parseInt(doc._rev, 10) : 0;
    doc._attachments = doc._attachments || {};
    doc._attachments[attachmentId] = {
      content_type: type,
      data: blob,
      revpos: ++prevrevpos
    };
    return api.put(doc);
  }

  return api.get(docId).then(function (doc) {
    if (doc._rev !== rev) {
      throw createError(REV_CONFLICT);
    }

    return createAttachment(doc);
  }, function (err) {
     // create new doc
    /* istanbul ignore else */
    if (err.reason === MISSING_DOC.message) {
      return createAttachment({_id: docId});
    } else {
      throw err;
    }
  });
});

AbstractPouchDB.prototype.removeAttachment =
  adapterFun('removeAttachment', function (docId, attachmentId, rev,
                                                 callback) {
  var self = this;
  self.get(docId, function (err, obj) {
    /* istanbul ignore if */
    if (err) {
      callback(err);
      return;
    }
    if (obj._rev !== rev) {
      callback(createError(REV_CONFLICT));
      return;
    }
    /* istanbul ignore if */
    if (!obj._attachments) {
      return callback();
    }
    delete obj._attachments[attachmentId];
    if (Object.keys(obj._attachments).length === 0) {
      delete obj._attachments;
    }
    self.put(obj, callback);
  });
});

AbstractPouchDB.prototype.remove =
  adapterFun('remove', function (docOrId, optsOrRev, opts, callback) {
  var doc;
  if (typeof optsOrRev === 'string') {
    // id, rev, opts, callback style
    doc = {
      _id: docOrId,
      _rev: optsOrRev
    };
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
  } else {
    // doc, opts, callback style
    doc = docOrId;
    if (typeof optsOrRev === 'function') {
      callback = optsOrRev;
      opts = {};
    } else {
      callback = opts;
      opts = optsOrRev;
    }
  }
  opts = opts || {};
  opts.was_delete = true;
  var newDoc = {_id: doc._id, _rev: (doc._rev || opts.rev)};
  newDoc._deleted = true;
  if (isLocalId(newDoc._id) && typeof this._removeLocal === 'function') {
    return this._removeLocal(doc, callback);
  }
  this.bulkDocs({docs: [newDoc]}, opts, yankError(callback));
});

AbstractPouchDB.prototype.revsDiff =
  adapterFun('revsDiff', function (req, opts, callback) {
  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }
  var ids = Object.keys(req);

  if (!ids.length) {
    return callback(null, {});
  }

  var count = 0;
  var missing = new _Map();

  function addToMissing(id, revId) {
    if (!missing.has(id)) {
      missing.set(id, {missing: []});
    }
    missing.get(id).missing.push(revId);
  }

  function processDoc(id, rev_tree) {
    // Is this fast enough? Maybe we should switch to a set simulated by a map
    var missingForId = req[id].slice(0);
    traverseRevTree(rev_tree, function (isLeaf, pos, revHash, ctx,
      opts) {
        var rev = pos + '-' + revHash;
        var idx = missingForId.indexOf(rev);
        if (idx === -1) {
          return;
        }

        missingForId.splice(idx, 1);
        /* istanbul ignore if */
        if (opts.status !== 'available') {
          addToMissing(id, rev);
        }
      });

    // Traversing the tree is synchronous, so now `missingForId` contains
    // revisions that were not found in the tree
    missingForId.forEach(function (rev) {
      addToMissing(id, rev);
    });
  }

  ids.map(function (id) {
    this._getRevisionTree(id, function (err, rev_tree) {
      if (err && err.status === 404 && err.message === 'missing') {
        missing.set(id, {missing: req[id]});
      } else if (err) {
        /* istanbul ignore next */
        return callback(err);
      } else {
        processDoc(id, rev_tree);
      }

      if (++count === ids.length) {
        // convert LazyMap to object
        var missingObj = {};
        missing.forEach(function (value, key) {
          missingObj[key] = value;
        });
        return callback(null, missingObj);
      }
    });
  }, this);
});

// _bulk_get API for faster replication, as described in
// https://github.com/apache/couchdb-chttpd/pull/33
// At the "abstract" level, it will just run multiple get()s in
// parallel, because this isn't much of a performance cost
// for local databases (except the cost of multiple transactions, which is
// small). The http adapter overrides this in order
// to do a more efficient single HTTP request.
AbstractPouchDB.prototype.bulkGet =
  adapterFun('bulkGet', function (opts, callback) {
  bulkGet(this, opts, callback);
});

// compact one document and fire callback
// by compacting we mean removing all revisions which
// are further from the leaf in revision tree than max_height
AbstractPouchDB.prototype.compactDocument =
  adapterFun('compactDocument', function (docId, maxHeight, callback) {
  var self = this;
  this._getRevisionTree(docId, function (err, revTree) {
    /* istanbul ignore if */
    if (err) {
      return callback(err);
    }
    var height = computeHeight(revTree);
    var candidates = [];
    var revs = [];
    Object.keys(height).forEach(function (rev) {
      if (height[rev] > maxHeight) {
        candidates.push(rev);
      }
    });

    traverseRevTree(revTree, function (isLeaf, pos, revHash, ctx, opts) {
      var rev = pos + '-' + revHash;
      if (opts.status === 'available' && candidates.indexOf(rev) !== -1) {
        revs.push(rev);
      }
    });
    self._doCompaction(docId, revs, callback);
  });
});

// compact the whole database using single document
// compaction
AbstractPouchDB.prototype.compact =
  adapterFun('compact', function (opts, callback) {
  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }

  var self = this;
  opts = opts || {};

  self._compactionQueue = self._compactionQueue || [];
  self._compactionQueue.push({opts: opts, callback: callback});
  if (self._compactionQueue.length === 1) {
    doNextCompaction(self);
  }
});
AbstractPouchDB.prototype._compact = function (opts, callback) {
  var self = this;
  var changesOpts = {
    return_docs: false,
    last_seq: opts.last_seq || 0
  };
  var promises = [];

  function onChange(row) {
    promises.push(self.compactDocument(row.id, 0));
  }
  function onComplete(resp) {
    var lastSeq = resp.last_seq;
    PouchPromise.all(promises).then(function () {
      return upsert(self, '_local/compaction', function deltaFunc(doc) {
        if (!doc.last_seq || doc.last_seq < lastSeq) {
          doc.last_seq = lastSeq;
          return doc;
        }
        return false; // somebody else got here first, don't update
      });
    }).then(function () {
      callback(null, {ok: true});
    }).catch(callback);
  }
  self.changes(changesOpts)
    .on('change', onChange)
    .on('complete', onComplete)
    .on('error', callback);
};

/* Begin api wrappers. Specific functionality to storage belongs in the
   _[method] */
AbstractPouchDB.prototype.get = adapterFun('get', function (id, opts, cb) {
  if (typeof opts === 'function') {
    cb = opts;
    opts = {};
  }
  if (typeof id !== 'string') {
    return cb(createError(INVALID_ID));
  }
  if (isLocalId(id) && typeof this._getLocal === 'function') {
    return this._getLocal(id, cb);
  }
  var leaves = [], self = this;

  function finishOpenRevs() {
    var result = [];
    var count = leaves.length;
    /* istanbul ignore if */
    if (!count) {
      return cb(null, result);
    }
    // order with open_revs is unspecified
    leaves.forEach(function (leaf) {
      self.get(id, {
        rev: leaf,
        revs: opts.revs,
        attachments: opts.attachments
      }, function (err, doc) {
        if (!err) {
          result.push({ok: doc});
        } else {
          result.push({missing: leaf});
        }
        count--;
        if (!count) {
          cb(null, result);
        }
      });
    });
  }

  if (opts.open_revs) {
    if (opts.open_revs === "all") {
      this._getRevisionTree(id, function (err, rev_tree) {
        if (err) {
          return cb(err);
        }
        leaves = collectLeaves(rev_tree).map(function (leaf) {
          return leaf.rev;
        });
        finishOpenRevs();
      });
    } else {
      if (Array.isArray(opts.open_revs)) {
        leaves = opts.open_revs;
        for (var i = 0; i < leaves.length; i++) {
          var l = leaves[i];
          // looks like it's the only thing couchdb checks
          if (!(typeof (l) === "string" && /^\d+-/.test(l))) {
            return cb(createError(INVALID_REV));
          }
        }
        finishOpenRevs();
      } else {
        return cb(createError(UNKNOWN_ERROR, 'function_clause'));
      }
    }
    return; // open_revs does not like other options
  }

  return this._get(id, opts, function (err, result) {
    if (err) {
      return cb(err);
    }

    var doc = result.doc;
    var metadata = result.metadata;
    var ctx = result.ctx;

    if (opts.conflicts) {
      var conflicts = collectConflicts(metadata);
      if (conflicts.length) {
        doc._conflicts = conflicts;
      }
    }

    if (isDeleted(metadata, doc._rev)) {
      doc._deleted = true;
    }

    if (opts.revs || opts.revs_info) {
      var paths = rootToLeaf(metadata.rev_tree);
      var path = arrayFirst(paths, function (arr) {
        return arr.ids.map(function (x) { return x.id; })
          .indexOf(doc._rev.split('-')[1]) !== -1;
      });

      var indexOfRev = path.ids.map(function (x) {return x.id; })
        .indexOf(doc._rev.split('-')[1]) + 1;
      var howMany = path.ids.length - indexOfRev;
      path.ids.splice(indexOfRev, howMany);
      path.ids.reverse();

      if (opts.revs) {
        doc._revisions = {
          start: (path.pos + path.ids.length) - 1,
          ids: path.ids.map(function (rev) {
            return rev.id;
          })
        };
      }
      if (opts.revs_info) {
        var pos =  path.pos + path.ids.length;
        doc._revs_info = path.ids.map(function (rev) {
          pos--;
          return {
            rev: pos + '-' + rev.id,
            status: rev.opts.status
          };
        });
      }
    }

    if (opts.attachments && doc._attachments) {
      var attachments = doc._attachments;
      var count = Object.keys(attachments).length;
      if (count === 0) {
        return cb(null, doc);
      }
      Object.keys(attachments).forEach(function (key) {
        this._getAttachment(doc._id, key, attachments[key], {
          // Previously the revision handling was done in adapter.js
          // getAttachment, however since idb-next doesnt we need to
          // pass the rev through
          rev: doc._rev,
          binary: opts.binary,
          ctx: ctx
        }, function (err, data) {
          var att = doc._attachments[key];
          att.data = data;
          delete att.stub;
          delete att.length;
          if (!--count) {
            cb(null, doc);
          }
        });
      }, self);
    } else {
      if (doc._attachments) {
        for (var key in doc._attachments) {
          /* istanbul ignore else */
          if (doc._attachments.hasOwnProperty(key)) {
            doc._attachments[key].stub = true;
          }
        }
      }
      cb(null, doc);
    }
  });
});

// TODO: I dont like this, it forces an extra read for every
// attachment read and enforces a confusing api between
// adapter.js and the adapter implementation
AbstractPouchDB.prototype.getAttachment =
  adapterFun('getAttachment', function (docId, attachmentId, opts, callback) {
  var self = this;
  if (opts instanceof Function) {
    callback = opts;
    opts = {};
  }
  this._get(docId, opts, function (err, res) {
    if (err) {
      return callback(err);
    }
    if (res.doc._attachments && res.doc._attachments[attachmentId]) {
      opts.ctx = res.ctx;
      opts.binary = true;
      self._getAttachment(docId, attachmentId,
                          res.doc._attachments[attachmentId], opts, callback);
    } else {
      return callback(createError(MISSING_DOC));
    }
  });
});

AbstractPouchDB.prototype.allDocs =
  adapterFun('allDocs', function (opts, callback) {
  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }
  opts.skip = typeof opts.skip !== 'undefined' ? opts.skip : 0;
  if (opts.start_key) {
    opts.startkey = opts.start_key;
  }
  if (opts.end_key) {
    opts.endkey = opts.end_key;
  }
  if ('keys' in opts) {
    if (!Array.isArray(opts.keys)) {
      return callback(new TypeError('options.keys must be an array'));
    }
    var incompatibleOpt =
      ['startkey', 'endkey', 'key'].filter(function (incompatibleOpt) {
      return incompatibleOpt in opts;
    })[0];
    if (incompatibleOpt) {
      callback(createError(QUERY_PARSE_ERROR,
        'Query parameter `' + incompatibleOpt +
        '` is not compatible with multi-get'
      ));
      return;
    }
    if (this.type() !== 'http') {
      return allDocsKeysQuery(this, opts, callback);
    }
  }

  return this._allDocs(opts, callback);
});

AbstractPouchDB.prototype.changes = function (opts, callback) {
  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }
  return new Changes$1(this, opts, callback);
};

AbstractPouchDB.prototype.close = adapterFun('close', function (callback) {
  this._closed = true;
  return this._close(callback);
});

AbstractPouchDB.prototype.info = adapterFun('info', function (callback) {
  var self = this;
  this._info(function (err, info) {
    if (err) {
      return callback(err);
    }
    // assume we know better than the adapter, unless it informs us
    info.db_name = info.db_name || self.name;
    info.auto_compaction = !!(self.auto_compaction && self.type() !== 'http');
    info.adapter = self.type();
    callback(null, info);
  });
});

AbstractPouchDB.prototype.id = adapterFun('id', function (callback) {
  return this._id(callback);
});

/* istanbul ignore next */
AbstractPouchDB.prototype.type = function () {
  return (typeof this._type === 'function') ? this._type() : this.adapter;
};

AbstractPouchDB.prototype.bulkDocs =
  adapterFun('bulkDocs', function (req, opts, callback) {
  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }

  opts = opts || {};

  if (Array.isArray(req)) {
    req = {
      docs: req
    };
  }

  if (!req || !req.docs || !Array.isArray(req.docs)) {
    return callback(createError(MISSING_BULK_DOCS));
  }

  for (var i = 0; i < req.docs.length; ++i) {
    if (typeof req.docs[i] !== 'object' || Array.isArray(req.docs[i])) {
      return callback(createError(NOT_AN_OBJECT));
    }
  }

  var attachmentError;
  req.docs.forEach(function (doc) {
    if (doc._attachments) {
      Object.keys(doc._attachments).forEach(function (name) {
        attachmentError = attachmentError || attachmentNameError(name);
      });
    }
  });

  if (attachmentError) {
    return callback(createError(BAD_REQUEST, attachmentError));
  }

  if (!('new_edits' in opts)) {
    if ('new_edits' in req) {
      opts.new_edits = req.new_edits;
    } else {
      opts.new_edits = true;
    }
  }

  if (!opts.new_edits && this.type() !== 'http') {
    // ensure revisions of the same doc are sorted, so that
    // the local adapter processes them correctly (#2935)
    req.docs.sort(compareByIdThenRev);
  }

  cleanDocs(req.docs);

  return this._bulkDocs(req, opts, function (err, res) {
    if (err) {
      return callback(err);
    }
    if (!opts.new_edits) {
      // this is what couch does when new_edits is false
      res = res.filter(function (x) {
        return x.error;
      });
    }
    callback(null, res);
  });
});

AbstractPouchDB.prototype.registerDependentDatabase =
  adapterFun('registerDependentDatabase', function (dependentDb,
                                                          callback) {
  var depDB = new this.constructor(dependentDb, this.__opts);

  function diffFun(doc) {
    doc.dependentDbs = doc.dependentDbs || {};
    if (doc.dependentDbs[dependentDb]) {
      return false; // no update required
    }
    doc.dependentDbs[dependentDb] = true;
    return doc;
  }
  upsert(this, '_local/_pouch_dependentDbs', diffFun)
    .then(function () {
      callback(null, {db: depDB});
    }).catch(callback);
});

AbstractPouchDB.prototype.destroy =
  adapterFun('destroy', function (opts, callback) {

  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }

  var self = this;
  var usePrefix = 'use_prefix' in self ? self.use_prefix : true;

  function destroyDb() {
    // call destroy method of the particular adaptor
    self._destroy(opts, function (err, resp) {
      if (err) {
        return callback(err);
      }
      self._destroyed = true;
      self.emit('destroyed');
      callback(null, resp || { 'ok': true });
    });
  }

  if (self.type() === 'http') {
    // no need to check for dependent DBs if it's a remote DB
    return destroyDb();
  }

  self.get('_local/_pouch_dependentDbs', function (err, localDoc) {
    if (err) {
      /* istanbul ignore if */
      if (err.status !== 404) {
        return callback(err);
      } else { // no dependencies
        return destroyDb();
      }
    }
    var dependentDbs = localDoc.dependentDbs;
    var PouchDB = self.constructor;
    var deletedMap = Object.keys(dependentDbs).map(function (name) {
      // use_prefix is only false in the browser
      /* istanbul ignore next */
      var trueName = usePrefix ?
        name.replace(new RegExp('^' + PouchDB.prefix), '') : name;
      return new PouchDB(trueName, self.__opts).destroy();
    });
    PouchPromise.all(deletedMap).then(destroyDb, callback);
  });
});

function TaskQueue() {
  this.isReady = false;
  this.failed = false;
  this.queue = [];
}

TaskQueue.prototype.execute = function () {
  var fun;
  if (this.failed) {
    while ((fun = this.queue.shift())) {
      fun(this.failed);
    }
  } else {
    while ((fun = this.queue.shift())) {
      fun();
    }
  }
};

TaskQueue.prototype.fail = function (err) {
  this.failed = err;
  this.execute();
};

TaskQueue.prototype.ready = function (db) {
  this.isReady = true;
  this.db = db;
  this.execute();
};

TaskQueue.prototype.addTask = function (fun) {
  this.queue.push(fun);
  if (this.failed) {
    this.execute();
  }
};

function parseAdapter(name, opts) {
  var match = name.match(/([a-z\-]*):\/\/(.*)/);
  if (match) {
    // the http adapter expects the fully qualified name
    name = /http(s?)/.test(match[1]) ? match[1] + '://' + match[2] : match[2];
    return {name: name, adapter: match[1]};
  }

  // check for browsers that have been upgraded from websql-only to websql+idb
  var skipIdb = 'idb' in PouchDB.adapters && 'websql' in PouchDB.adapters &&
    hasLocalStorage() &&
    localStorage['_pouch__websqldb_' + PouchDB.prefix + name];

  var adapterName;

  if (opts.adapter) {
    adapterName = opts.adapter;
  } else if (typeof opts !== 'undefined' && opts.db) {
    adapterName = 'leveldb';
  } else { // automatically determine adapter
    for (var i = 0; i < PouchDB.preferredAdapters.length; ++i) {
      adapterName = PouchDB.preferredAdapters[i];
      /* istanbul ignore if */
      if (skipIdb && adapterName === 'idb') {
        // log it, because this can be confusing during development
        guardedConsole('log', 'PouchDB is downgrading "' + name + '" to WebSQL to' +
          ' avoid data loss, because it was already opened with WebSQL.');
        continue; // keep using websql to avoid user data loss
      }
      break;
    }
  }

  var adapter = PouchDB.adapters[adapterName];

  // if adapter is invalid, then an error will be thrown later
  var usePrefix = (adapter && 'use_prefix' in adapter) ?
    adapter.use_prefix : true;

  return {
    name: usePrefix ? (PouchDB.prefix + name) : name,
    adapter: adapterName
  };
}

// OK, so here's the deal. Consider this code:
//     var db1 = new PouchDB('foo');
//     var db2 = new PouchDB('foo');
//     db1.destroy();
// ^ these two both need to emit 'destroyed' events,
// as well as the PouchDB constructor itself.
// So we have one db object (whichever one got destroy() called on it)
// responsible for emitting the initial event, which then gets emitted
// by the constructor, which then broadcasts it to any other dbs
// that may have been created with the same name.
function prepareForDestruction(self) {

  var destructionListeners = self.constructor._destructionListeners;

  function onDestroyed() {
    self.constructor.emit('destroyed', self.name);
  }

  function onConstructorDestroyed() {
    self.removeListener('destroyed', onDestroyed);
    self.emit('destroyed', self);
  }

  self.once('destroyed', onDestroyed);

  // in setup.js, the constructor is primed to listen for destroy events
  if (!destructionListeners.has(self.name)) {
    destructionListeners.set(self.name, []);
  }
  destructionListeners.get(self.name).push(onConstructorDestroyed);
}

inherits(PouchDB, AbstractPouchDB);
function PouchDB(name, opts) {
  // In Node our test suite only tests this for PouchAlt unfortunately
  /* istanbul ignore if */
  if (!(this instanceof PouchDB)) {
    return new PouchDB(name, opts);
  }

  var self = this;
  opts = opts || {};

  if (name && typeof name === 'object') {
    opts = name;
    name = opts.name;
    delete opts.name;
  }

  this.__opts = opts = clone(opts);

  self.auto_compaction = opts.auto_compaction;
  self.prefix = PouchDB.prefix;

  if (typeof name !== 'string') {
    throw new Error('Missing/invalid DB name');
  }

  var prefixedName = (opts.prefix || '') + name;
  var backend = parseAdapter(prefixedName, opts);

  opts.name = backend.name;
  opts.adapter = opts.adapter || backend.adapter;

  self.name = name;
  self._adapter = opts.adapter;
  debug('pouchdb:adapter')('Picked adapter: ' + opts.adapter);

  if (!PouchDB.adapters[opts.adapter] ||
      !PouchDB.adapters[opts.adapter].valid()) {
    throw new Error('Invalid Adapter: ' + opts.adapter);
  }

  AbstractPouchDB.call(self);
  self.taskqueue = new TaskQueue();

  self.adapter = opts.adapter;

  PouchDB.adapters[opts.adapter].call(self, opts, function (err) {
    if (err) {
      return self.taskqueue.fail(err);
    }
    prepareForDestruction(self);

    self.emit('created', self);
    PouchDB.emit('created', self.name);
    self.taskqueue.ready(self);
  });

}

PouchDB.debug = debug;

PouchDB.adapters = {};
PouchDB.preferredAdapters = [];

PouchDB.prefix = '_pouch_';

var eventEmitter = new events.EventEmitter();

function setUpEventEmitter(Pouch) {
  Object.keys(events.EventEmitter.prototype).forEach(function (key) {
    if (typeof events.EventEmitter.prototype[key] === 'function') {
      Pouch[key] = eventEmitter[key].bind(eventEmitter);
    }
  });

  // these are created in constructor.js, and allow us to notify each DB with
  // the same name that it was destroyed, via the constructor object
  var destructListeners = Pouch._destructionListeners = new _Map();
  Pouch.on('destroyed', function onConstructorDestroyed(name) {
    destructListeners.get(name).forEach(function (callback) {
      callback();
    });
    destructListeners.delete(name);
  });
}

setUpEventEmitter(PouchDB);

PouchDB.adapter = function (id, obj, addToPreferredAdapters) {
  /* istanbul ignore else */
  if (obj.valid()) {
    PouchDB.adapters[id] = obj;
    if (addToPreferredAdapters) {
      PouchDB.preferredAdapters.push(id);
    }
  }
};

PouchDB.plugin = function (obj) {
  if (typeof obj === 'function') { // function style for plugins
    obj(PouchDB);
  } else if (typeof obj !== 'object' || Object.keys(obj).length === 0){
    throw new Error('Invalid plugin: object passed in is empty or not an object');
  } else {
    Object.keys(obj).forEach(function (id) { // object style for plugins
      PouchDB.prototype[id] = obj[id];
    });
  }
  return PouchDB;
};

PouchDB.defaults = function (defaultOpts) {
  function PouchAlt(name, opts) {
    if (!(this instanceof PouchAlt)) {
      return new PouchAlt(name, opts);
    }

    opts = opts || {};

    if (name && typeof name === 'object') {
      opts = name;
      name = opts.name;
      delete opts.name;
    }

    opts = extend$1({}, defaultOpts, opts);
    PouchDB.call(this, name, opts);
  }

  inherits(PouchAlt, PouchDB);

  PouchAlt.preferredAdapters = PouchDB.preferredAdapters.slice();
  Object.keys(PouchDB).forEach(function (key) {
    if (!(key in PouchAlt)) {
      PouchAlt[key] = PouchDB[key];
    }
  });

  return PouchAlt;
};

// managed automatically by set-version.js
var version = "6.0.7";

PouchDB.version = version;

function toObject(array) {
  return array.reduce(function (obj, item) {
    obj[item] = true;
    return obj;
  }, {});
}
// List of top level reserved words for doc
var reservedWords = toObject([
  '_id',
  '_rev',
  '_attachments',
  '_deleted',
  '_revisions',
  '_revs_info',
  '_conflicts',
  '_deleted_conflicts',
  '_local_seq',
  '_rev_tree',
  //replication documents
  '_replication_id',
  '_replication_state',
  '_replication_state_time',
  '_replication_state_reason',
  '_replication_stats',
  // Specific to Couchbase Sync Gateway
  '_removed'
]);

// List of reserved words that should end up the document
var dataWords = toObject([
  '_attachments',
  //replication documents
  '_replication_id',
  '_replication_state',
  '_replication_state_time',
  '_replication_state_reason',
  '_replication_stats'
]);

function parseRevisionInfo(rev) {
  if (!/^\d+\-./.test(rev)) {
    return createError(INVALID_REV);
  }
  var idx = rev.indexOf('-');
  var left = rev.substring(0, idx);
  var right = rev.substring(idx + 1);
  return {
    prefix: parseInt(left, 10),
    id: right
  };
}

function makeRevTreeFromRevisions(revisions, opts) {
  var pos = revisions.start - revisions.ids.length + 1;

  var revisionIds = revisions.ids;
  var ids = [revisionIds[0], opts, []];

  for (var i = 1, len = revisionIds.length; i < len; i++) {
    ids = [revisionIds[i], {status: 'missing'}, [ids]];
  }

  return [{
    pos: pos,
    ids: ids
  }];
}

// Preprocess documents, parse their revisions, assign an id and a
// revision for new writes that are missing them, etc
function parseDoc(doc, newEdits) {

  var nRevNum;
  var newRevId;
  var revInfo;
  var opts = {status: 'available'};
  if (doc._deleted) {
    opts.deleted = true;
  }

  if (newEdits) {
    if (!doc._id) {
      doc._id = uuid();
    }
    newRevId = uuid(32, 16).toLowerCase();
    if (doc._rev) {
      revInfo = parseRevisionInfo(doc._rev);
      if (revInfo.error) {
        return revInfo;
      }
      doc._rev_tree = [{
        pos: revInfo.prefix,
        ids: [revInfo.id, {status: 'missing'}, [[newRevId, opts, []]]]
      }];
      nRevNum = revInfo.prefix + 1;
    } else {
      doc._rev_tree = [{
        pos: 1,
        ids : [newRevId, opts, []]
      }];
      nRevNum = 1;
    }
  } else {
    if (doc._revisions) {
      doc._rev_tree = makeRevTreeFromRevisions(doc._revisions, opts);
      nRevNum = doc._revisions.start;
      newRevId = doc._revisions.ids[0];
    }
    if (!doc._rev_tree) {
      revInfo = parseRevisionInfo(doc._rev);
      if (revInfo.error) {
        return revInfo;
      }
      nRevNum = revInfo.prefix;
      newRevId = revInfo.id;
      doc._rev_tree = [{
        pos: nRevNum,
        ids: [newRevId, opts, []]
      }];
    }
  }

  invalidIdError(doc._id);

  doc._rev = nRevNum + '-' + newRevId;

  var result = {metadata : {}, data : {}};
  for (var key in doc) {
    /* istanbul ignore else */
    if (Object.prototype.hasOwnProperty.call(doc, key)) {
      var specialKey = key[0] === '_';
      if (specialKey && !reservedWords[key]) {
        var error = createError(DOC_VALIDATION, key);
        error.message = DOC_VALIDATION.message + ': ' + key;
        throw error;
      } else if (specialKey && !dataWords[key]) {
        result.metadata[key.slice(1)] = doc[key];
      } else {
        result.data[key] = doc[key];
      }
    }
  }
  return result;
}

var atob$1 = function (str) {
  return atob(str);
};

var btoa$1 = function (str) {
  return btoa(str);
};

// Abstracts constructing a Blob object, so it also works in older
// browsers that don't support the native Blob constructor (e.g.
// old QtWebKit versions, Android < 4.4).
function createBlob(parts, properties) {
  /* global BlobBuilder,MSBlobBuilder,MozBlobBuilder,WebKitBlobBuilder */
  parts = parts || [];
  properties = properties || {};
  try {
    return new Blob(parts, properties);
  } catch (e) {
    if (e.name !== "TypeError") {
      throw e;
    }
    var Builder = typeof BlobBuilder !== 'undefined' ? BlobBuilder :
                  typeof MSBlobBuilder !== 'undefined' ? MSBlobBuilder :
                  typeof MozBlobBuilder !== 'undefined' ? MozBlobBuilder :
                  WebKitBlobBuilder;
    var builder = new Builder();
    for (var i = 0; i < parts.length; i += 1) {
      builder.append(parts[i]);
    }
    return builder.getBlob(properties.type);
  }
}

// From http://stackoverflow.com/questions/14967647/ (continues on next line)
// encode-decode-image-with-base64-breaks-image (2013-04-21)
function binaryStringToArrayBuffer(bin) {
  var length = bin.length;
  var buf = new ArrayBuffer(length);
  var arr = new Uint8Array(buf);
  for (var i = 0; i < length; i++) {
    arr[i] = bin.charCodeAt(i);
  }
  return buf;
}

function binStringToBluffer(binString, type) {
  return createBlob([binaryStringToArrayBuffer(binString)], {type: type});
}

function b64ToBluffer(b64, type) {
  return binStringToBluffer(atob$1(b64), type);
}

//Can't find original post, but this is close
//http://stackoverflow.com/questions/6965107/ (continues on next line)
//converting-between-strings-and-arraybuffers
function arrayBufferToBinaryString(buffer) {
  var binary = '';
  var bytes = new Uint8Array(buffer);
  var length = bytes.byteLength;
  for (var i = 0; i < length; i++) {
    binary += String.fromCharCode(bytes[i]);
  }
  return binary;
}

// shim for browsers that don't support it
function readAsBinaryString(blob, callback) {
  if (typeof FileReader === 'undefined') {
    // fix for Firefox in a web worker
    // https://bugzilla.mozilla.org/show_bug.cgi?id=901097
    return callback(arrayBufferToBinaryString(
      new FileReaderSync().readAsArrayBuffer(blob)));
  }

  var reader = new FileReader();
  var hasBinaryString = typeof reader.readAsBinaryString === 'function';
  reader.onloadend = function (e) {
    var result = e.target.result || '';
    if (hasBinaryString) {
      return callback(result);
    }
    callback(arrayBufferToBinaryString(result));
  };
  if (hasBinaryString) {
    reader.readAsBinaryString(blob);
  } else {
    reader.readAsArrayBuffer(blob);
  }
}

function blobToBinaryString(blobOrBuffer, callback) {
  readAsBinaryString(blobOrBuffer, function (bin) {
    callback(bin);
  });
}

function blobToBase64(blobOrBuffer, callback) {
  blobToBinaryString(blobOrBuffer, function (base64) {
    callback(btoa$1(base64));
  });
}

// simplified API. universal browser support is assumed
function readAsArrayBuffer(blob, callback) {
  if (typeof FileReader === 'undefined') {
    // fix for Firefox in a web worker:
    // https://bugzilla.mozilla.org/show_bug.cgi?id=901097
    return callback(new FileReaderSync().readAsArrayBuffer(blob));
  }

  var reader = new FileReader();
  reader.onloadend = function (e) {
    var result = e.target.result || new ArrayBuffer(0);
    callback(result);
  };
  reader.readAsArrayBuffer(blob);
}

var setImmediateShim = global.setImmediate || global.setTimeout;
var MD5_CHUNK_SIZE = 32768;

function rawToBase64(raw) {
  return btoa$1(raw);
}

function sliceBlob(blob, start, end) {
  if (blob.webkitSlice) {
    return blob.webkitSlice(start, end);
  }
  return blob.slice(start, end);
}

function appendBlob(buffer, blob, start, end, callback) {
  if (start > 0 || end < blob.size) {
    // only slice blob if we really need to
    blob = sliceBlob(blob, start, end);
  }
  readAsArrayBuffer(blob, function (arrayBuffer) {
    buffer.append(arrayBuffer);
    callback();
  });
}

function appendString(buffer, string, start, end, callback) {
  if (start > 0 || end < string.length) {
    // only create a substring if we really need to
    string = string.substring(start, end);
  }
  buffer.appendBinary(string);
  callback();
}

function binaryMd5(data, callback) {
  var inputIsString = typeof data === 'string';
  var len = inputIsString ? data.length : data.size;
  var chunkSize = Math.min(MD5_CHUNK_SIZE, len);
  var chunks = Math.ceil(len / chunkSize);
  var currentChunk = 0;
  var buffer = inputIsString ? new Md5() : new Md5.ArrayBuffer();

  var append = inputIsString ? appendString : appendBlob;

  function next() {
    setImmediateShim(loadNextChunk);
  }

  function done() {
    var raw = buffer.end(true);
    var base64 = rawToBase64(raw);
    callback(base64);
    buffer.destroy();
  }

  function loadNextChunk() {
    var start = currentChunk * chunkSize;
    var end = start + chunkSize;
    currentChunk++;
    if (currentChunk < chunks) {
      append(buffer, data, start, end, next);
    } else {
      append(buffer, data, start, end, done);
    }
  }
  loadNextChunk();
}

function stringMd5(string) {
  return Md5.hash(string);
}

function parseBase64(data) {
  try {
    return atob$1(data);
  } catch (e) {
    var err = createError(BAD_ARG,
      'Attachment is not a valid base64 string');
    return {error: err};
  }
}

function preprocessString(att, blobType, callback) {
  var asBinary = parseBase64(att.data);
  if (asBinary.error) {
    return callback(asBinary.error);
  }

  att.length = asBinary.length;
  if (blobType === 'blob') {
    att.data = binStringToBluffer(asBinary, att.content_type);
  } else if (blobType === 'base64') {
    att.data = btoa$1(asBinary);
  } else { // binary
    att.data = asBinary;
  }
  binaryMd5(asBinary, function (result) {
    att.digest = 'md5-' + result;
    callback();
  });
}

function preprocessBlob(att, blobType, callback) {
  binaryMd5(att.data, function (md5) {
    att.digest = 'md5-' + md5;
    // size is for blobs (browser), length is for buffers (node)
    att.length = att.data.size || att.data.length || 0;
    if (blobType === 'binary') {
      blobToBinaryString(att.data, function (binString) {
        att.data = binString;
        callback();
      });
    } else if (blobType === 'base64') {
      blobToBase64(att.data, function (b64) {
        att.data = b64;
        callback();
      });
    } else {
      callback();
    }
  });
}

function preprocessAttachment(att, blobType, callback) {
  if (att.stub) {
    return callback();
  }
  if (typeof att.data === 'string') { // input is a base64 string
    preprocessString(att, blobType, callback);
  } else { // input is a blob
    preprocessBlob(att, blobType, callback);
  }
}

function preprocessAttachments(docInfos, blobType, callback) {

  if (!docInfos.length) {
    return callback();
  }

  var docv = 0;
  var overallErr;

  docInfos.forEach(function (docInfo) {
    var attachments = docInfo.data && docInfo.data._attachments ?
      Object.keys(docInfo.data._attachments) : [];
    var recv = 0;

    if (!attachments.length) {
      return done();
    }

    function processedAttachment(err) {
      overallErr = err;
      recv++;
      if (recv === attachments.length) {
        done();
      }
    }

    for (var key in docInfo.data._attachments) {
      if (docInfo.data._attachments.hasOwnProperty(key)) {
        preprocessAttachment(docInfo.data._attachments[key],
          blobType, processedAttachment);
      }
    }
  });

  function done() {
    docv++;
    if (docInfos.length === docv) {
      if (overallErr) {
        callback(overallErr);
      } else {
        callback();
      }
    }
  }
}

function updateDoc(revLimit, prev, docInfo, results,
                   i, cb, writeDoc, newEdits) {

  if (revExists(prev.rev_tree, docInfo.metadata.rev)) {
    results[i] = docInfo;
    return cb();
  }

  // sometimes this is pre-calculated. historically not always
  var previousWinningRev = prev.winningRev || winningRev(prev);
  var previouslyDeleted = 'deleted' in prev ? prev.deleted :
    isDeleted(prev, previousWinningRev);
  var deleted = 'deleted' in docInfo.metadata ? docInfo.metadata.deleted :
    isDeleted(docInfo.metadata);
  var isRoot = /^1-/.test(docInfo.metadata.rev);

  if (previouslyDeleted && !deleted && newEdits && isRoot) {
    var newDoc = docInfo.data;
    newDoc._rev = previousWinningRev;
    newDoc._id = docInfo.metadata.id;
    docInfo = parseDoc(newDoc, newEdits);
  }

  var merged = merge(prev.rev_tree, docInfo.metadata.rev_tree[0], revLimit);

  var inConflict = newEdits && (((previouslyDeleted && deleted) ||
    (!previouslyDeleted && merged.conflicts !== 'new_leaf') ||
    (previouslyDeleted && !deleted && merged.conflicts === 'new_branch')));

  if (inConflict) {
    var err = createError(REV_CONFLICT);
    results[i] = err;
    return cb();
  }

  var newRev = docInfo.metadata.rev;
  docInfo.metadata.rev_tree = merged.tree;
  docInfo.stemmedRevs = merged.stemmedRevs || [];
  /* istanbul ignore else */
  if (prev.rev_map) {
    docInfo.metadata.rev_map = prev.rev_map; // used only by leveldb
  }

  // recalculate
  var winningRev$$ = winningRev(docInfo.metadata);
  var winningRevIsDeleted = isDeleted(docInfo.metadata, winningRev$$);

  // calculate the total number of documents that were added/removed,
  // from the perspective of total_rows/doc_count
  var delta = (previouslyDeleted === winningRevIsDeleted) ? 0 :
    previouslyDeleted < winningRevIsDeleted ? -1 : 1;

  var newRevIsDeleted;
  if (newRev === winningRev$$) {
    // if the new rev is the same as the winning rev, we can reuse that value
    newRevIsDeleted = winningRevIsDeleted;
  } else {
    // if they're not the same, then we need to recalculate
    newRevIsDeleted = isDeleted(docInfo.metadata, newRev);
  }

  writeDoc(docInfo, winningRev$$, winningRevIsDeleted, newRevIsDeleted,
    true, delta, i, cb);
}

function rootIsMissing(docInfo) {
  return docInfo.metadata.rev_tree[0].ids[1].status === 'missing';
}

function processDocs(revLimit, docInfos, api, fetchedDocs, tx, results,
                     writeDoc, opts, overallCallback) {

  // Default to 1000 locally
  revLimit = revLimit || 1000;

  function insertDoc(docInfo, resultsIdx, callback) {
    // Cant insert new deleted documents
    var winningRev$$ = winningRev(docInfo.metadata);
    var deleted = isDeleted(docInfo.metadata, winningRev$$);
    if ('was_delete' in opts && deleted) {
      results[resultsIdx] = createError(MISSING_DOC, 'deleted');
      return callback();
    }

    // 4712 - detect whether a new document was inserted with a _rev
    var inConflict = newEdits && rootIsMissing(docInfo);

    if (inConflict) {
      var err = createError(REV_CONFLICT);
      results[resultsIdx] = err;
      return callback();
    }

    var delta = deleted ? 0 : 1;

    writeDoc(docInfo, winningRev$$, deleted, deleted, false,
      delta, resultsIdx, callback);
  }

  var newEdits = opts.new_edits;
  var idsToDocs = new _Map();

  var docsDone = 0;
  var docsToDo = docInfos.length;

  function checkAllDocsDone() {
    if (++docsDone === docsToDo && overallCallback) {
      overallCallback();
    }
  }

  docInfos.forEach(function (currentDoc, resultsIdx) {

    if (currentDoc._id && isLocalId(currentDoc._id)) {
      var fun = currentDoc._deleted ? '_removeLocal' : '_putLocal';
      api[fun](currentDoc, {ctx: tx}, function (err, res) {
        results[resultsIdx] = err || res;
        checkAllDocsDone();
      });
      return;
    }

    var id = currentDoc.metadata.id;
    if (idsToDocs.has(id)) {
      docsToDo--; // duplicate
      idsToDocs.get(id).push([currentDoc, resultsIdx]);
    } else {
      idsToDocs.set(id, [[currentDoc, resultsIdx]]);
    }
  });

  // in the case of new_edits, the user can provide multiple docs
  // with the same id. these need to be processed sequentially
  idsToDocs.forEach(function (docs, id) {
    var numDone = 0;

    function docWritten() {
      if (++numDone < docs.length) {
        nextDoc();
      } else {
        checkAllDocsDone();
      }
    }
    function nextDoc() {
      var value = docs[numDone];
      var currentDoc = value[0];
      var resultsIdx = value[1];

      if (fetchedDocs.has(id)) {
        updateDoc(revLimit, fetchedDocs.get(id), currentDoc, results,
          resultsIdx, docWritten, writeDoc, newEdits);
      } else {
        // Ensure stemming applies to new writes as well
        var merged = merge([], currentDoc.metadata.rev_tree[0], revLimit);
        currentDoc.metadata.rev_tree = merged.tree;
        currentDoc.stemmedRevs = merged.stemmedRevs || [];
        insertDoc(currentDoc, resultsIdx, docWritten);
      }
    }
    nextDoc();
  });
}

// IndexedDB requires a versioned database structure, so we use the
// version here to manage migrations.
var ADAPTER_VERSION = 5;

// The object stores created for each database
// DOC_STORE stores the document meta data, its revision history and state
// Keyed by document id
var DOC_STORE = 'document-store';
// BY_SEQ_STORE stores a particular version of a document, keyed by its
// sequence id
var BY_SEQ_STORE = 'by-sequence';
// Where we store attachments
var ATTACH_STORE = 'attach-store';
// Where we store many-to-many relations
// between attachment digests and seqs
var ATTACH_AND_SEQ_STORE = 'attach-seq-store';

// Where we store database-wide meta data in a single record
// keyed by id: META_STORE
var META_STORE = 'meta-store';
// Where we store local documents
var LOCAL_STORE = 'local-store';
// Where we detect blob support
var DETECT_BLOB_SUPPORT_STORE = 'detect-blob-support';

function slowJsonParse(str) {
  try {
    return JSON.parse(str);
  } catch (e) {
    /* istanbul ignore next */
    return vuvuzela.parse(str);
  }
}

function safeJsonParse(str) {
  // try/catch is deoptimized in V8, leading to slower
  // times than we'd like to have. Most documents are _not_
  // huge, and do not require a slower code path just to parse them.
  // We can be pretty sure that a document under 50000 characters
  // will not be so deeply nested as to throw a stack overflow error
  // (depends on the engine and available memory, though, so this is
  // just a hunch). 50000 was chosen based on the average length
  // of this string in our test suite, to try to find a number that covers
  // most of our test cases (26 over this size, 26378 under it).
  if (str.length < 50000) {
    return JSON.parse(str);
  }
  return slowJsonParse(str);
}

function safeJsonStringify(json) {
  try {
    return JSON.stringify(json);
  } catch (e) {
    /* istanbul ignore next */
    return vuvuzela.stringify(json);
  }
}

function tryCode(fun, that, args, PouchDB) {
  try {
    fun.apply(that, args);
  } catch (err) {
    // Shouldn't happen, but in some odd cases
    // IndexedDB implementations might throw a sync
    // error, in which case this will at least log it.
    PouchDB.emit('error', err);
  }
}

var taskQueue = {
  running: false,
  queue: []
};

function applyNext(PouchDB) {
  if (taskQueue.running || !taskQueue.queue.length) {
    return;
  }
  taskQueue.running = true;
  var item = taskQueue.queue.shift();
  item.action(function (err, res) {
    tryCode(item.callback, this, [err, res], PouchDB);
    taskQueue.running = false;
    process.nextTick(function () {
      applyNext(PouchDB);
    });
  });
}

function idbError(callback) {
  return function (evt) {
    var message = 'unknown_error';
    if (evt.target && evt.target.error) {
      message = evt.target.error.name || evt.target.error.message;
    }
    callback(createError(IDB_ERROR, message, evt.type));
  };
}

// Unfortunately, the metadata has to be stringified
// when it is put into the database, because otherwise
// IndexedDB can throw errors for deeply-nested objects.
// Originally we just used JSON.parse/JSON.stringify; now
// we use this custom vuvuzela library that avoids recursion.
// If we could do it all over again, we'd probably use a
// format for the revision trees other than JSON.
function encodeMetadata(metadata, winningRev, deleted) {
  return {
    data: safeJsonStringify(metadata),
    winningRev: winningRev,
    deletedOrLocal: deleted ? '1' : '0',
    seq: metadata.seq, // highest seq for this doc
    id: metadata.id
  };
}

function decodeMetadata(storedObject) {
  if (!storedObject) {
    return null;
  }
  var metadata = safeJsonParse(storedObject.data);
  metadata.winningRev = storedObject.winningRev;
  metadata.deleted = storedObject.deletedOrLocal === '1';
  metadata.seq = storedObject.seq;
  return metadata;
}

// read the doc back out from the database. we don't store the
// _id or _rev because we already have _doc_id_rev.
function decodeDoc(doc) {
  if (!doc) {
    return doc;
  }
  var idx = doc._doc_id_rev.lastIndexOf(':');
  doc._id = doc._doc_id_rev.substring(0, idx - 1);
  doc._rev = doc._doc_id_rev.substring(idx + 1);
  delete doc._doc_id_rev;
  return doc;
}

// Read a blob from the database, encoding as necessary
// and translating from base64 if the IDB doesn't support
// native Blobs
function readBlobData(body, type, asBlob, callback) {
  if (asBlob) {
    if (!body) {
      callback(createBlob([''], {type: type}));
    } else if (typeof body !== 'string') { // we have blob support
      callback(body);
    } else { // no blob support
      callback(b64ToBluffer(body, type));
    }
  } else { // as base64 string
    if (!body) {
      callback('');
    } else if (typeof body !== 'string') { // we have blob support
      readAsBinaryString(body, function (binary) {
        callback(btoa$1(binary));
      });
    } else { // no blob support
      callback(body);
    }
  }
}

function fetchAttachmentsIfNecessary(doc, opts, txn, cb) {
  var attachments = Object.keys(doc._attachments || {});
  if (!attachments.length) {
    return cb && cb();
  }
  var numDone = 0;

  function checkDone() {
    if (++numDone === attachments.length && cb) {
      cb();
    }
  }

  function fetchAttachment(doc, att) {
    var attObj = doc._attachments[att];
    var digest = attObj.digest;
    var req = txn.objectStore(ATTACH_STORE).get(digest);
    req.onsuccess = function (e) {
      attObj.body = e.target.result.body;
      checkDone();
    };
  }

  attachments.forEach(function (att) {
    if (opts.attachments && opts.include_docs) {
      fetchAttachment(doc, att);
    } else {
      doc._attachments[att].stub = true;
      checkDone();
    }
  });
}

// IDB-specific postprocessing necessary because
// we don't know whether we stored a true Blob or
// a base64-encoded string, and if it's a Blob it
// needs to be read outside of the transaction context
function postProcessAttachments(results, asBlob) {
  return PouchPromise.all(results.map(function (row) {
    if (row.doc && row.doc._attachments) {
      var attNames = Object.keys(row.doc._attachments);
      return PouchPromise.all(attNames.map(function (att) {
        var attObj = row.doc._attachments[att];
        if (!('body' in attObj)) { // already processed
          return;
        }
        var body = attObj.body;
        var type = attObj.content_type;
        return new PouchPromise(function (resolve) {
          readBlobData(body, type, asBlob, function (data) {
            row.doc._attachments[att] = extend$1(
              pick(attObj, ['digest', 'content_type']),
              {data: data}
            );
            resolve();
          });
        });
      }));
    }
  }));
}

function compactRevs(revs, docId, txn) {

  var possiblyOrphanedDigests = [];
  var seqStore = txn.objectStore(BY_SEQ_STORE);
  var attStore = txn.objectStore(ATTACH_STORE);
  var attAndSeqStore = txn.objectStore(ATTACH_AND_SEQ_STORE);
  var count = revs.length;

  function checkDone() {
    count--;
    if (!count) { // done processing all revs
      deleteOrphanedAttachments();
    }
  }

  function deleteOrphanedAttachments() {
    if (!possiblyOrphanedDigests.length) {
      return;
    }
    possiblyOrphanedDigests.forEach(function (digest) {
      var countReq = attAndSeqStore.index('digestSeq').count(
        IDBKeyRange.bound(
          digest + '::', digest + '::\uffff', false, false));
      countReq.onsuccess = function (e) {
        var count = e.target.result;
        if (!count) {
          // orphaned
          attStore.delete(digest);
        }
      };
    });
  }

  revs.forEach(function (rev) {
    var index = seqStore.index('_doc_id_rev');
    var key = docId + "::" + rev;
    index.getKey(key).onsuccess = function (e) {
      var seq = e.target.result;
      if (typeof seq !== 'number') {
        return checkDone();
      }
      seqStore.delete(seq);

      var cursor = attAndSeqStore.index('seq')
        .openCursor(IDBKeyRange.only(seq));

      cursor.onsuccess = function (event) {
        var cursor = event.target.result;
        if (cursor) {
          var digest = cursor.value.digestSeq.split('::')[0];
          possiblyOrphanedDigests.push(digest);
          attAndSeqStore.delete(cursor.primaryKey);
          cursor.continue();
        } else { // done
          checkDone();
        }
      };
    };
  });
}

function openTransactionSafely(idb, stores, mode) {
  try {
    return {
      txn: idb.transaction(stores, mode)
    };
  } catch (err) {
    return {
      error: err
    };
  }
}

function idbBulkDocs(dbOpts, req, opts, api, idb, idbChanges, callback) {
  var docInfos = req.docs;
  var txn;
  var docStore;
  var bySeqStore;
  var attachStore;
  var attachAndSeqStore;
  var docInfoError;
  var docCountDelta = 0;

  for (var i = 0, len = docInfos.length; i < len; i++) {
    var doc = docInfos[i];
    if (doc._id && isLocalId(doc._id)) {
      continue;
    }
    doc = docInfos[i] = parseDoc(doc, opts.new_edits);
    if (doc.error && !docInfoError) {
      docInfoError = doc;
    }
  }

  if (docInfoError) {
    return callback(docInfoError);
  }

  var results = new Array(docInfos.length);
  var fetchedDocs = new _Map();
  var preconditionErrored = false;
  var blobType = api._meta.blobSupport ? 'blob' : 'base64';

  preprocessAttachments(docInfos, blobType, function (err) {
    if (err) {
      return callback(err);
    }
    startTransaction();
  });

  function startTransaction() {

    var stores = [
      DOC_STORE, BY_SEQ_STORE,
      ATTACH_STORE,
      LOCAL_STORE, ATTACH_AND_SEQ_STORE
    ];
    var txnResult = openTransactionSafely(idb, stores, 'readwrite');
    if (txnResult.error) {
      return callback(txnResult.error);
    }
    txn = txnResult.txn;
    txn.onabort = idbError(callback);
    txn.ontimeout = idbError(callback);
    txn.oncomplete = complete;
    docStore = txn.objectStore(DOC_STORE);
    bySeqStore = txn.objectStore(BY_SEQ_STORE);
    attachStore = txn.objectStore(ATTACH_STORE);
    attachAndSeqStore = txn.objectStore(ATTACH_AND_SEQ_STORE);

    verifyAttachments(function (err) {
      if (err) {
        preconditionErrored = true;
        return callback(err);
      }
      fetchExistingDocs();
    });
  }

  function idbProcessDocs() {
    processDocs(dbOpts.revs_limit, docInfos, api, fetchedDocs,
                txn, results, writeDoc, opts);
  }

  function fetchExistingDocs() {

    if (!docInfos.length) {
      return;
    }

    var numFetched = 0;

    function checkDone() {
      if (++numFetched === docInfos.length) {
        idbProcessDocs();
      }
    }

    function readMetadata(event) {
      var metadata = decodeMetadata(event.target.result);

      if (metadata) {
        fetchedDocs.set(metadata.id, metadata);
      }
      checkDone();
    }

    for (var i = 0, len = docInfos.length; i < len; i++) {
      var docInfo = docInfos[i];
      if (docInfo._id && isLocalId(docInfo._id)) {
        checkDone(); // skip local docs
        continue;
      }
      var req = docStore.get(docInfo.metadata.id);
      req.onsuccess = readMetadata;
    }
  }

  function complete() {
    if (preconditionErrored) {
      return;
    }

    idbChanges.notify(api._meta.name);
    api._meta.docCount += docCountDelta;
    callback(null, results);
  }

  function verifyAttachment(digest, callback) {

    var req = attachStore.get(digest);
    req.onsuccess = function (e) {
      if (!e.target.result) {
        var err = createError(MISSING_STUB,
          'unknown stub attachment with digest ' +
          digest);
        err.status = 412;
        callback(err);
      } else {
        callback();
      }
    };
  }

  function verifyAttachments(finish) {


    var digests = [];
    docInfos.forEach(function (docInfo) {
      if (docInfo.data && docInfo.data._attachments) {
        Object.keys(docInfo.data._attachments).forEach(function (filename) {
          var att = docInfo.data._attachments[filename];
          if (att.stub) {
            digests.push(att.digest);
          }
        });
      }
    });
    if (!digests.length) {
      return finish();
    }
    var numDone = 0;
    var err;

    function checkDone() {
      if (++numDone === digests.length) {
        finish(err);
      }
    }
    digests.forEach(function (digest) {
      verifyAttachment(digest, function (attErr) {
        if (attErr && !err) {
          err = attErr;
        }
        checkDone();
      });
    });
  }

  function writeDoc(docInfo, winningRev, winningRevIsDeleted, newRevIsDeleted,
                    isUpdate, delta, resultsIdx, callback) {

    docCountDelta += delta;

    docInfo.metadata.winningRev = winningRev;
    docInfo.metadata.deleted = winningRevIsDeleted;

    var doc = docInfo.data;
    doc._id = docInfo.metadata.id;
    doc._rev = docInfo.metadata.rev;

    if (newRevIsDeleted) {
      doc._deleted = true;
    }

    var hasAttachments = doc._attachments &&
      Object.keys(doc._attachments).length;
    if (hasAttachments) {
      return writeAttachments(docInfo, winningRev, winningRevIsDeleted,
        isUpdate, resultsIdx, callback);
    }

    finishDoc(docInfo, winningRev, winningRevIsDeleted,
      isUpdate, resultsIdx, callback);
  }

  function finishDoc(docInfo, winningRev, winningRevIsDeleted,
                     isUpdate, resultsIdx, callback) {

    var doc = docInfo.data;
    var metadata = docInfo.metadata;

    doc._doc_id_rev = metadata.id + '::' + metadata.rev;
    delete doc._id;
    delete doc._rev;

    function afterPutDoc(e) {
      var revsToDelete = docInfo.stemmedRevs || [];

      if (isUpdate && api.auto_compaction) {
        revsToDelete = revsToDelete.concat(compactTree(docInfo.metadata));
      }

      if (revsToDelete && revsToDelete.length) {
        compactRevs(revsToDelete, docInfo.metadata.id, txn);
      }

      metadata.seq = e.target.result;
      // Current _rev is calculated from _rev_tree on read
      delete metadata.rev;
      var metadataToStore = encodeMetadata(metadata, winningRev,
        winningRevIsDeleted);
      var metaDataReq = docStore.put(metadataToStore);
      metaDataReq.onsuccess = afterPutMetadata;
    }

    function afterPutDocError(e) {
      // ConstraintError, need to update, not put (see #1638 for details)
      e.preventDefault(); // avoid transaction abort
      e.stopPropagation(); // avoid transaction onerror
      var index = bySeqStore.index('_doc_id_rev');
      var getKeyReq = index.getKey(doc._doc_id_rev);
      getKeyReq.onsuccess = function (e) {
        var putReq = bySeqStore.put(doc, e.target.result);
        putReq.onsuccess = afterPutDoc;
      };
    }

    function afterPutMetadata() {
      results[resultsIdx] = {
        ok: true,
        id: metadata.id,
        rev: winningRev
      };
      fetchedDocs.set(docInfo.metadata.id, docInfo.metadata);
      insertAttachmentMappings(docInfo, metadata.seq, callback);
    }

    var putReq = bySeqStore.put(doc);

    putReq.onsuccess = afterPutDoc;
    putReq.onerror = afterPutDocError;
  }

  function writeAttachments(docInfo, winningRev, winningRevIsDeleted,
                            isUpdate, resultsIdx, callback) {


    var doc = docInfo.data;

    var numDone = 0;
    var attachments = Object.keys(doc._attachments);

    function collectResults() {
      if (numDone === attachments.length) {
        finishDoc(docInfo, winningRev, winningRevIsDeleted,
          isUpdate, resultsIdx, callback);
      }
    }

    function attachmentSaved() {
      numDone++;
      collectResults();
    }

    attachments.forEach(function (key) {
      var att = docInfo.data._attachments[key];
      if (!att.stub) {
        var data = att.data;
        delete att.data;
        att.revpos = parseInt(winningRev, 10);
        var digest = att.digest;
        saveAttachment(digest, data, attachmentSaved);
      } else {
        numDone++;
        collectResults();
      }
    });
  }

  // map seqs to attachment digests, which
  // we will need later during compaction
  function insertAttachmentMappings(docInfo, seq, callback) {

    var attsAdded = 0;
    var attsToAdd = Object.keys(docInfo.data._attachments || {});

    if (!attsToAdd.length) {
      return callback();
    }

    function checkDone() {
      if (++attsAdded === attsToAdd.length) {
        callback();
      }
    }

    function add(att) {
      var digest = docInfo.data._attachments[att].digest;
      var req = attachAndSeqStore.put({
        seq: seq,
        digestSeq: digest + '::' + seq
      });

      req.onsuccess = checkDone;
      req.onerror = function (e) {
        // this callback is for a constaint error, which we ignore
        // because this docid/rev has already been associated with
        // the digest (e.g. when new_edits == false)
        e.preventDefault(); // avoid transaction abort
        e.stopPropagation(); // avoid transaction onerror
        checkDone();
      };
    }
    for (var i = 0; i < attsToAdd.length; i++) {
      add(attsToAdd[i]); // do in parallel
    }
  }

  function saveAttachment(digest, data, callback) {


    var getKeyReq = attachStore.count(digest);
    getKeyReq.onsuccess = function (e) {
      var count = e.target.result;
      if (count) {
        return callback(); // already exists
      }
      var newAtt = {
        digest: digest,
        body: data
      };
      var putReq = attachStore.put(newAtt);
      putReq.onsuccess = callback;
    };
  }
}

function createKeyRange(start, end, inclusiveEnd, key, descending) {
  try {
    if (start && end) {
      if (descending) {
        return IDBKeyRange.bound(end, start, !inclusiveEnd, false);
      } else {
        return IDBKeyRange.bound(start, end, false, !inclusiveEnd);
      }
    } else if (start) {
      if (descending) {
        return IDBKeyRange.upperBound(start);
      } else {
        return IDBKeyRange.lowerBound(start);
      }
    } else if (end) {
      if (descending) {
        return IDBKeyRange.lowerBound(end, !inclusiveEnd);
      } else {
        return IDBKeyRange.upperBound(end, !inclusiveEnd);
      }
    } else if (key) {
      return IDBKeyRange.only(key);
    }
  } catch (e) {
    return {error: e};
  }
  return null;
}

function handleKeyRangeError(api, opts, err, callback) {
  if (err.name === "DataError" && err.code === 0) {
    // data error, start is less than end
    return callback(null, {
      total_rows: api._meta.docCount,
      offset: opts.skip,
      rows: []
    });
  }
  callback(createError(IDB_ERROR, err.name, err.message));
}

function idbAllDocs(opts, api, idb, callback) {

  function allDocsQuery(opts, callback) {
    var start = 'startkey' in opts ? opts.startkey : false;
    var end = 'endkey' in opts ? opts.endkey : false;
    var key = 'key' in opts ? opts.key : false;
    var skip = opts.skip || 0;
    var limit = typeof opts.limit === 'number' ? opts.limit : -1;
    var inclusiveEnd = opts.inclusive_end !== false;
    var descending = 'descending' in opts && opts.descending ? 'prev' : null;

    var keyRange = createKeyRange(start, end, inclusiveEnd, key, descending);
    if (keyRange && keyRange.error) {
      return handleKeyRangeError(api, opts, keyRange.error, callback);
    }

    var stores = [DOC_STORE, BY_SEQ_STORE];

    if (opts.attachments) {
      stores.push(ATTACH_STORE);
    }
    var txnResult = openTransactionSafely(idb, stores, 'readonly');
    if (txnResult.error) {
      return callback(txnResult.error);
    }
    var txn = txnResult.txn;
    var docStore = txn.objectStore(DOC_STORE);
    var seqStore = txn.objectStore(BY_SEQ_STORE);
    var cursor = descending ?
      docStore.openCursor(keyRange, descending) :
      docStore.openCursor(keyRange);
    var docIdRevIndex = seqStore.index('_doc_id_rev');
    var results = [];
    var docCount = 0;

    // if the user specifies include_docs=true, then we don't
    // want to block the main cursor while we're fetching the doc
    function fetchDocAsynchronously(metadata, row, winningRev) {
      var key = metadata.id + "::" + winningRev;
      docIdRevIndex.get(key).onsuccess =  function onGetDoc(e) {
        row.doc = decodeDoc(e.target.result);
        if (opts.conflicts) {
          row.doc._conflicts = collectConflicts(metadata);
        }
        fetchAttachmentsIfNecessary(row.doc, opts, txn);
      };
    }

    function allDocsInner(cursor, winningRev, metadata) {
      var row = {
        id: metadata.id,
        key: metadata.id,
        value: {
          rev: winningRev
        }
      };
      var deleted = metadata.deleted;
      if (opts.deleted === 'ok') {
        results.push(row);
        // deleted docs are okay with "keys" requests
        if (deleted) {
          row.value.deleted = true;
          row.doc = null;
        } else if (opts.include_docs) {
          fetchDocAsynchronously(metadata, row, winningRev);
        }
      } else if (!deleted && skip-- <= 0) {
        results.push(row);
        if (opts.include_docs) {
          fetchDocAsynchronously(metadata, row, winningRev);
        }
        if (--limit === 0) {
          return;
        }
      }
      cursor.continue();
    }

    function onGetCursor(e) {
      docCount = api._meta.docCount; // do this within the txn for consistency
      var cursor = e.target.result;
      if (!cursor) {
        return;
      }
      var metadata = decodeMetadata(cursor.value);
      var winningRev = metadata.winningRev;

      allDocsInner(cursor, winningRev, metadata);
    }

    function onResultsReady() {
      callback(null, {
        total_rows: docCount,
        offset: opts.skip,
        rows: results
      });
    }

    function onTxnComplete() {
      if (opts.attachments) {
        postProcessAttachments(results, opts.binary).then(onResultsReady);
      } else {
        onResultsReady();
      }
    }

    txn.oncomplete = onTxnComplete;
    cursor.onsuccess = onGetCursor;
  }

  function allDocs(opts, callback) {

    if (opts.limit === 0) {
      return callback(null, {
        total_rows: api._meta.docCount,
        offset: opts.skip,
        rows: []
      });
    }
    allDocsQuery(opts, callback);
  }

  allDocs(opts, callback);
}

//
// Blobs are not supported in all versions of IndexedDB, notably
// Chrome <37 and Android <5. In those versions, storing a blob will throw.
//
// Various other blob bugs exist in Chrome v37-42 (inclusive).
// Detecting them is expensive and confusing to users, and Chrome 37-42
// is at very low usage worldwide, so we do a hacky userAgent check instead.
//
// content-type bug: https://code.google.com/p/chromium/issues/detail?id=408120
// 404 bug: https://code.google.com/p/chromium/issues/detail?id=447916
// FileReader bug: https://code.google.com/p/chromium/issues/detail?id=447836
//
function checkBlobSupport(txn) {
  return new PouchPromise(function (resolve) {
    var blob = createBlob(['']);
    txn.objectStore(DETECT_BLOB_SUPPORT_STORE).put(blob, 'key');

    txn.onabort = function (e) {
      // If the transaction aborts now its due to not being able to
      // write to the database, likely due to the disk being full
      e.preventDefault();
      e.stopPropagation();
      resolve(false);
    };

    txn.oncomplete = function () {
      var matchedChrome = navigator.userAgent.match(/Chrome\/(\d+)/);
      var matchedEdge = navigator.userAgent.match(/Edge\//);
      // MS Edge pretends to be Chrome 42:
      // https://msdn.microsoft.com/en-us/library/hh869301%28v=vs.85%29.aspx
      resolve(matchedEdge || !matchedChrome ||
        parseInt(matchedChrome[1], 10) >= 43);
    };
  }).catch(function () {
    return false; // error, so assume unsupported
  });
}

var cachedDBs = new _Map();
var blobSupportPromise;
var idbChanges = new Changes();
var openReqList = new _Map();

function IdbPouch(opts, callback) {
  var api = this;

  taskQueue.queue.push({
    action: function (thisCallback) {
      init(api, opts, thisCallback);
    },
    callback: callback
  });
  applyNext(api.constructor);
}

function init(api, opts, callback) {

  var dbName = opts.name;

  var idb = null;
  api._meta = null;

  // called when creating a fresh new database
  function createSchema(db) {
    var docStore = db.createObjectStore(DOC_STORE, {keyPath : 'id'});
    db.createObjectStore(BY_SEQ_STORE, {autoIncrement: true})
      .createIndex('_doc_id_rev', '_doc_id_rev', {unique: true});
    db.createObjectStore(ATTACH_STORE, {keyPath: 'digest'});
    db.createObjectStore(META_STORE, {keyPath: 'id', autoIncrement: false});
    db.createObjectStore(DETECT_BLOB_SUPPORT_STORE);

    // added in v2
    docStore.createIndex('deletedOrLocal', 'deletedOrLocal', {unique : false});

    // added in v3
    db.createObjectStore(LOCAL_STORE, {keyPath: '_id'});

    // added in v4
    var attAndSeqStore = db.createObjectStore(ATTACH_AND_SEQ_STORE,
      {autoIncrement: true});
    attAndSeqStore.createIndex('seq', 'seq');
    attAndSeqStore.createIndex('digestSeq', 'digestSeq', {unique: true});
  }

  // migration to version 2
  // unfortunately "deletedOrLocal" is a misnomer now that we no longer
  // store local docs in the main doc-store, but whaddyagonnado
  function addDeletedOrLocalIndex(txn, callback) {
    var docStore = txn.objectStore(DOC_STORE);
    docStore.createIndex('deletedOrLocal', 'deletedOrLocal', {unique : false});

    docStore.openCursor().onsuccess = function (event) {
      var cursor = event.target.result;
      if (cursor) {
        var metadata = cursor.value;
        var deleted = isDeleted(metadata);
        metadata.deletedOrLocal = deleted ? "1" : "0";
        docStore.put(metadata);
        cursor.continue();
      } else {
        callback();
      }
    };
  }

  // migration to version 3 (part 1)
  function createLocalStoreSchema(db) {
    db.createObjectStore(LOCAL_STORE, {keyPath: '_id'})
      .createIndex('_doc_id_rev', '_doc_id_rev', {unique: true});
  }

  // migration to version 3 (part 2)
  function migrateLocalStore(txn, cb) {
    var localStore = txn.objectStore(LOCAL_STORE);
    var docStore = txn.objectStore(DOC_STORE);
    var seqStore = txn.objectStore(BY_SEQ_STORE);

    var cursor = docStore.openCursor();
    cursor.onsuccess = function (event) {
      var cursor = event.target.result;
      if (cursor) {
        var metadata = cursor.value;
        var docId = metadata.id;
        var local = isLocalId(docId);
        var rev = winningRev(metadata);
        if (local) {
          var docIdRev = docId + "::" + rev;
          // remove all seq entries
          // associated with this docId
          var start = docId + "::";
          var end = docId + "::~";
          var index = seqStore.index('_doc_id_rev');
          var range = IDBKeyRange.bound(start, end, false, false);
          var seqCursor = index.openCursor(range);
          seqCursor.onsuccess = function (e) {
            seqCursor = e.target.result;
            if (!seqCursor) {
              // done
              docStore.delete(cursor.primaryKey);
              cursor.continue();
            } else {
              var data = seqCursor.value;
              if (data._doc_id_rev === docIdRev) {
                localStore.put(data);
              }
              seqStore.delete(seqCursor.primaryKey);
              seqCursor.continue();
            }
          };
        } else {
          cursor.continue();
        }
      } else if (cb) {
        cb();
      }
    };
  }

  // migration to version 4 (part 1)
  function addAttachAndSeqStore(db) {
    var attAndSeqStore = db.createObjectStore(ATTACH_AND_SEQ_STORE,
      {autoIncrement: true});
    attAndSeqStore.createIndex('seq', 'seq');
    attAndSeqStore.createIndex('digestSeq', 'digestSeq', {unique: true});
  }

  // migration to version 4 (part 2)
  function migrateAttsAndSeqs(txn, callback) {
    var seqStore = txn.objectStore(BY_SEQ_STORE);
    var attStore = txn.objectStore(ATTACH_STORE);
    var attAndSeqStore = txn.objectStore(ATTACH_AND_SEQ_STORE);

    // need to actually populate the table. this is the expensive part,
    // so as an optimization, check first that this database even
    // contains attachments
    var req = attStore.count();
    req.onsuccess = function (e) {
      var count = e.target.result;
      if (!count) {
        return callback(); // done
      }

      seqStore.openCursor().onsuccess = function (e) {
        var cursor = e.target.result;
        if (!cursor) {
          return callback(); // done
        }
        var doc = cursor.value;
        var seq = cursor.primaryKey;
        var atts = Object.keys(doc._attachments || {});
        var digestMap = {};
        for (var j = 0; j < atts.length; j++) {
          var att = doc._attachments[atts[j]];
          digestMap[att.digest] = true; // uniq digests, just in case
        }
        var digests = Object.keys(digestMap);
        for (j = 0; j < digests.length; j++) {
          var digest = digests[j];
          attAndSeqStore.put({
            seq: seq,
            digestSeq: digest + '::' + seq
          });
        }
        cursor.continue();
      };
    };
  }

  // migration to version 5
  // Instead of relying on on-the-fly migration of metadata,
  // this brings the doc-store to its modern form:
  // - metadata.winningrev
  // - metadata.seq
  // - stringify the metadata when storing it
  function migrateMetadata(txn) {

    function decodeMetadataCompat(storedObject) {
      if (!storedObject.data) {
        // old format, when we didn't store it stringified
        storedObject.deleted = storedObject.deletedOrLocal === '1';
        return storedObject;
      }
      return decodeMetadata(storedObject);
    }

    // ensure that every metadata has a winningRev and seq,
    // which was previously created on-the-fly but better to migrate
    var bySeqStore = txn.objectStore(BY_SEQ_STORE);
    var docStore = txn.objectStore(DOC_STORE);
    var cursor = docStore.openCursor();
    cursor.onsuccess = function (e) {
      var cursor = e.target.result;
      if (!cursor) {
        return; // done
      }
      var metadata = decodeMetadataCompat(cursor.value);

      metadata.winningRev = metadata.winningRev ||
        winningRev(metadata);

      function fetchMetadataSeq() {
        // metadata.seq was added post-3.2.0, so if it's missing,
        // we need to fetch it manually
        var start = metadata.id + '::';
        var end = metadata.id + '::\uffff';
        var req = bySeqStore.index('_doc_id_rev').openCursor(
          IDBKeyRange.bound(start, end));

        var metadataSeq = 0;
        req.onsuccess = function (e) {
          var cursor = e.target.result;
          if (!cursor) {
            metadata.seq = metadataSeq;
            return onGetMetadataSeq();
          }
          var seq = cursor.primaryKey;
          if (seq > metadataSeq) {
            metadataSeq = seq;
          }
          cursor.continue();
        };
      }

      function onGetMetadataSeq() {
        var metadataToStore = encodeMetadata(metadata,
          metadata.winningRev, metadata.deleted);

        var req = docStore.put(metadataToStore);
        req.onsuccess = function () {
          cursor.continue();
        };
      }

      if (metadata.seq) {
        return onGetMetadataSeq();
      }

      fetchMetadataSeq();
    };

  }

  api.type = function () {
    return 'idb';
  };

  api._id = toPromise(function (callback) {
    callback(null, api._meta.instanceId);
  });

  api._bulkDocs = function idb_bulkDocs(req, reqOpts, callback) {
    idbBulkDocs(opts, req, reqOpts, api, idb, idbChanges, callback);
  };

  // First we look up the metadata in the ids database, then we fetch the
  // current revision(s) from the by sequence store
  api._get = function idb_get(id, opts, callback) {
    var doc;
    var metadata;
    var err;
    var txn = opts.ctx;
    if (!txn) {
      var txnResult = openTransactionSafely(idb,
        [DOC_STORE, BY_SEQ_STORE, ATTACH_STORE], 'readonly');
      if (txnResult.error) {
        return callback(txnResult.error);
      }
      txn = txnResult.txn;
    }

    function finish() {
      callback(err, {doc: doc, metadata: metadata, ctx: txn});
    }

    txn.objectStore(DOC_STORE).get(id).onsuccess = function (e) {
      metadata = decodeMetadata(e.target.result);
      // we can determine the result here if:
      // 1. there is no such document
      // 2. the document is deleted and we don't ask about specific rev
      // When we ask with opts.rev we expect the answer to be either
      // doc (possibly with _deleted=true) or missing error
      if (!metadata) {
        err = createError(MISSING_DOC, 'missing');
        return finish();
      }
      if (isDeleted(metadata) && !opts.rev) {
        err = createError(MISSING_DOC, "deleted");
        return finish();
      }
      var objectStore = txn.objectStore(BY_SEQ_STORE);

      var rev = opts.rev || metadata.winningRev;
      var key = metadata.id + '::' + rev;

      objectStore.index('_doc_id_rev').get(key).onsuccess = function (e) {
        doc = e.target.result;
        if (doc) {
          doc = decodeDoc(doc);
        }
        if (!doc) {
          err = createError(MISSING_DOC, 'missing');
          return finish();
        }
        finish();
      };
    };
  };

  api._getAttachment = function (docId, attachId, attachment, opts, callback) {
    var txn;
    if (opts.ctx) {
      txn = opts.ctx;
    } else {
      var txnResult = openTransactionSafely(idb,
        [DOC_STORE, BY_SEQ_STORE, ATTACH_STORE], 'readonly');
      if (txnResult.error) {
        return callback(txnResult.error);
      }
      txn = txnResult.txn;
    }
    var digest = attachment.digest;
    var type = attachment.content_type;

    txn.objectStore(ATTACH_STORE).get(digest).onsuccess = function (e) {
      var body = e.target.result.body;
      readBlobData(body, type, opts.binary, function (blobData) {
        callback(null, blobData);
      });
    };
  };

  api._info = function idb_info(callback) {

    if (idb === null || !cachedDBs.has(dbName)) {
      var error = new Error('db isn\'t open');
      error.id = 'idbNull';
      return callback(error);
    }
    var updateSeq;
    var docCount;

    var txnResult = openTransactionSafely(idb, [BY_SEQ_STORE], 'readonly');
    if (txnResult.error) {
      return callback(txnResult.error);
    }
    var txn = txnResult.txn;
    var cursor = txn.objectStore(BY_SEQ_STORE).openCursor(null, 'prev');
    cursor.onsuccess = function (event) {
      var cursor = event.target.result;
      updateSeq = cursor ? cursor.key : 0;
      // count within the same txn for consistency
      docCount = api._meta.docCount;
    };

    txn.oncomplete = function () {
      callback(null, {
        doc_count: docCount,
        update_seq: updateSeq,
        // for debugging
        idb_attachment_format: (api._meta.blobSupport ? 'binary' : 'base64')
      });
    };
  };

  api._allDocs = function idb_allDocs(opts, callback) {
    idbAllDocs(opts, api, idb, callback);
  };

  api._changes = function (opts) {
    opts = clone(opts);

    if (opts.continuous) {
      var id = dbName + ':' + uuid();
      idbChanges.addListener(dbName, id, api, opts);
      idbChanges.notify(dbName);
      return {
        cancel: function () {
          idbChanges.removeListener(dbName, id);
        }
      };
    }

    var docIds = opts.doc_ids && new _Set(opts.doc_ids);

    opts.since = opts.since || 0;
    var lastSeq = opts.since;

    var limit = 'limit' in opts ? opts.limit : -1;
    if (limit === 0) {
      limit = 1; // per CouchDB _changes spec
    }
    var returnDocs;
    if ('return_docs' in opts) {
      returnDocs = opts.return_docs;
    } else if ('returnDocs' in opts) {
      // TODO: Remove 'returnDocs' in favor of 'return_docs' in a future release
      returnDocs = opts.returnDocs;
    } else {
      returnDocs = true;
    }

    var results = [];
    var numResults = 0;
    var filter = filterChange(opts);
    var docIdsToMetadata = new _Map();

    var txn;
    var bySeqStore;
    var docStore;
    var docIdRevIndex;

    function onGetCursor(cursor) {

      var doc = decodeDoc(cursor.value);
      var seq = cursor.key;

      if (docIds && !docIds.has(doc._id)) {
        return cursor.continue();
      }

      var metadata;

      function onGetMetadata() {
        if (metadata.seq !== seq) {
          // some other seq is later
          return cursor.continue();
        }

        lastSeq = seq;

        if (metadata.winningRev === doc._rev) {
          return onGetWinningDoc(doc);
        }

        fetchWinningDoc();
      }

      function fetchWinningDoc() {
        var docIdRev = doc._id + '::' + metadata.winningRev;
        var req = docIdRevIndex.get(docIdRev);
        req.onsuccess = function (e) {
          onGetWinningDoc(decodeDoc(e.target.result));
        };
      }

      function onGetWinningDoc(winningDoc) {

        var change = opts.processChange(winningDoc, metadata, opts);
        change.seq = metadata.seq;

        var filtered = filter(change);
        if (typeof filtered === 'object') {
          return opts.complete(filtered);
        }

        if (filtered) {
          numResults++;
          if (returnDocs) {
            results.push(change);
          }
          // process the attachment immediately
          // for the benefit of live listeners
          if (opts.attachments && opts.include_docs) {
            fetchAttachmentsIfNecessary(winningDoc, opts, txn, function () {
              postProcessAttachments([change], opts.binary).then(function () {
                opts.onChange(change);
              });
            });
          } else {
            opts.onChange(change);
          }
        }
        if (numResults !== limit) {
          cursor.continue();
        }
      }

      metadata = docIdsToMetadata.get(doc._id);
      if (metadata) { // cached
        return onGetMetadata();
      }
      // metadata not cached, have to go fetch it
      docStore.get(doc._id).onsuccess = function (event) {
        metadata = decodeMetadata(event.target.result);
        docIdsToMetadata.set(doc._id, metadata);
        onGetMetadata();
      };
    }

    function onsuccess(event) {
      var cursor = event.target.result;

      if (!cursor) {
        return;
      }
      onGetCursor(cursor);
    }

    function fetchChanges() {
      var objectStores = [DOC_STORE, BY_SEQ_STORE];
      if (opts.attachments) {
        objectStores.push(ATTACH_STORE);
      }
      var txnResult = openTransactionSafely(idb, objectStores, 'readonly');
      if (txnResult.error) {
        return opts.complete(txnResult.error);
      }
      txn = txnResult.txn;
      txn.onabort = idbError(opts.complete);
      txn.oncomplete = onTxnComplete;

      bySeqStore = txn.objectStore(BY_SEQ_STORE);
      docStore = txn.objectStore(DOC_STORE);
      docIdRevIndex = bySeqStore.index('_doc_id_rev');

      var req;

      if (opts.descending) {
        req = bySeqStore.openCursor(null, 'prev');
      } else {
        req = bySeqStore.openCursor(IDBKeyRange.lowerBound(opts.since, true));
      }

      req.onsuccess = onsuccess;
    }

    fetchChanges();

    function onTxnComplete() {

      function finish() {
        opts.complete(null, {
          results: results,
          last_seq: lastSeq
        });
      }

      if (!opts.continuous && opts.attachments) {
        // cannot guarantee that postProcessing was already done,
        // so do it again
        postProcessAttachments(results).then(finish);
      } else {
        finish();
      }
    }
  };

  api._close = function (callback) {
    if (idb === null) {
      return callback(createError(NOT_OPEN));
    }

    // https://developer.mozilla.org/en-US/docs/IndexedDB/IDBDatabase#close
    // "Returns immediately and closes the connection in a separate thread..."
    idb.close();
    cachedDBs.delete(dbName);
    idb = null;
    callback();
  };

  api._getRevisionTree = function (docId, callback) {
    var txnResult = openTransactionSafely(idb, [DOC_STORE], 'readonly');
    if (txnResult.error) {
      return callback(txnResult.error);
    }
    var txn = txnResult.txn;
    var req = txn.objectStore(DOC_STORE).get(docId);
    req.onsuccess = function (event) {
      var doc = decodeMetadata(event.target.result);
      if (!doc) {
        callback(createError(MISSING_DOC));
      } else {
        callback(null, doc.rev_tree);
      }
    };
  };

  // This function removes revisions of document docId
  // which are listed in revs and sets this document
  // revision to to rev_tree
  api._doCompaction = function (docId, revs, callback) {
    var stores = [
      DOC_STORE,
      BY_SEQ_STORE,
      ATTACH_STORE,
      ATTACH_AND_SEQ_STORE
    ];
    var txnResult = openTransactionSafely(idb, stores, 'readwrite');
    if (txnResult.error) {
      return callback(txnResult.error);
    }
    var txn = txnResult.txn;

    var docStore = txn.objectStore(DOC_STORE);

    docStore.get(docId).onsuccess = function (event) {
      var metadata = decodeMetadata(event.target.result);
      traverseRevTree(metadata.rev_tree, function (isLeaf, pos,
                                                         revHash, ctx, opts) {
        var rev = pos + '-' + revHash;
        if (revs.indexOf(rev) !== -1) {
          opts.status = 'missing';
        }
      });
      compactRevs(revs, docId, txn);
      var winningRev = metadata.winningRev;
      var deleted = metadata.deleted;
      txn.objectStore(DOC_STORE).put(
        encodeMetadata(metadata, winningRev, deleted));
    };
    txn.onabort = idbError(callback);
    txn.oncomplete = function () {
      callback();
    };
  };


  api._getLocal = function (id, callback) {
    var txnResult = openTransactionSafely(idb, [LOCAL_STORE], 'readonly');
    if (txnResult.error) {
      return callback(txnResult.error);
    }
    var tx = txnResult.txn;
    var req = tx.objectStore(LOCAL_STORE).get(id);

    req.onerror = idbError(callback);
    req.onsuccess = function (e) {
      var doc = e.target.result;
      if (!doc) {
        callback(createError(MISSING_DOC));
      } else {
        delete doc['_doc_id_rev']; // for backwards compat
        callback(null, doc);
      }
    };
  };

  api._putLocal = function (doc, opts, callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    delete doc._revisions; // ignore this, trust the rev
    var oldRev = doc._rev;
    var id = doc._id;
    if (!oldRev) {
      doc._rev = '0-1';
    } else {
      doc._rev = '0-' + (parseInt(oldRev.split('-')[1], 10) + 1);
    }

    var tx = opts.ctx;
    var ret;
    if (!tx) {
      var txnResult = openTransactionSafely(idb, [LOCAL_STORE], 'readwrite');
      if (txnResult.error) {
        return callback(txnResult.error);
      }
      tx = txnResult.txn;
      tx.onerror = idbError(callback);
      tx.oncomplete = function () {
        if (ret) {
          callback(null, ret);
        }
      };
    }

    var oStore = tx.objectStore(LOCAL_STORE);
    var req;
    if (oldRev) {
      req = oStore.get(id);
      req.onsuccess = function (e) {
        var oldDoc = e.target.result;
        if (!oldDoc || oldDoc._rev !== oldRev) {
          callback(createError(REV_CONFLICT));
        } else { // update
          var req = oStore.put(doc);
          req.onsuccess = function () {
            ret = {ok: true, id: doc._id, rev: doc._rev};
            if (opts.ctx) { // return immediately
              callback(null, ret);
            }
          };
        }
      };
    } else { // new doc
      req = oStore.add(doc);
      req.onerror = function (e) {
        // constraint error, already exists
        callback(createError(REV_CONFLICT));
        e.preventDefault(); // avoid transaction abort
        e.stopPropagation(); // avoid transaction onerror
      };
      req.onsuccess = function () {
        ret = {ok: true, id: doc._id, rev: doc._rev};
        if (opts.ctx) { // return immediately
          callback(null, ret);
        }
      };
    }
  };

  api._removeLocal = function (doc, opts, callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    var tx = opts.ctx;
    if (!tx) {
      var txnResult = openTransactionSafely(idb, [LOCAL_STORE], 'readwrite');
      if (txnResult.error) {
        return callback(txnResult.error);
      }
      tx = txnResult.txn;
      tx.oncomplete = function () {
        if (ret) {
          callback(null, ret);
        }
      };
    }
    var ret;
    var id = doc._id;
    var oStore = tx.objectStore(LOCAL_STORE);
    var req = oStore.get(id);

    req.onerror = idbError(callback);
    req.onsuccess = function (e) {
      var oldDoc = e.target.result;
      if (!oldDoc || oldDoc._rev !== doc._rev) {
        callback(createError(MISSING_DOC));
      } else {
        oStore.delete(id);
        ret = {ok: true, id: id, rev: '0-0'};
        if (opts.ctx) { // return immediately
          callback(null, ret);
        }
      }
    };
  };

  api._destroy = function (opts, callback) {
    idbChanges.removeAllListeners(dbName);

    //Close open request for "dbName" database to fix ie delay.
    var openReq = openReqList.get(dbName);
    if (openReq && openReq.result) {
      openReq.result.close();
      cachedDBs.delete(dbName);
    }
    var req = indexedDB.deleteDatabase(dbName);

    req.onsuccess = function () {
      //Remove open request from the list.
      openReqList.delete(dbName);
      if (hasLocalStorage() && (dbName in localStorage)) {
        delete localStorage[dbName];
      }
      callback(null, { 'ok': true });
    };

    req.onerror = idbError(callback);
  };

  var cached = cachedDBs.get(dbName);

  if (cached) {
    idb = cached.idb;
    api._meta = cached.global;
    process.nextTick(function () {
      callback(null, api);
    });
    return;
  }

  var req;
  if (opts.storage) {
    req = tryStorageOption(dbName, opts.storage);
  } else {
    req = indexedDB.open(dbName, ADAPTER_VERSION);
  }

  openReqList.set(dbName, req);

  req.onupgradeneeded = function (e) {
    var db = e.target.result;
    if (e.oldVersion < 1) {
      return createSchema(db); // new db, initial schema
    }
    // do migrations

    var txn = e.currentTarget.transaction;
    // these migrations have to be done in this function, before
    // control is returned to the event loop, because IndexedDB

    if (e.oldVersion < 3) {
      createLocalStoreSchema(db); // v2 -> v3
    }
    if (e.oldVersion < 4) {
      addAttachAndSeqStore(db); // v3 -> v4
    }

    var migrations = [
      addDeletedOrLocalIndex, // v1 -> v2
      migrateLocalStore,      // v2 -> v3
      migrateAttsAndSeqs,     // v3 -> v4
      migrateMetadata         // v4 -> v5
    ];

    var i = e.oldVersion;

    function next() {
      var migration = migrations[i - 1];
      i++;
      if (migration) {
        migration(txn, next);
      }
    }

    next();
  };

  req.onsuccess = function (e) {

    idb = e.target.result;

    idb.onversionchange = function () {
      idb.close();
      cachedDBs.delete(dbName);
    };

    idb.onabort = function (e) {
      guardedConsole('error', 'Database has a global failure', e.target.error);
      idb.close();
      cachedDBs.delete(dbName);
    };

    var txn = idb.transaction([
      META_STORE,
      DETECT_BLOB_SUPPORT_STORE,
      DOC_STORE
    ], 'readwrite');

    var req = txn.objectStore(META_STORE).get(META_STORE);

    var blobSupport = null;
    var docCount = null;
    var instanceId = null;

    req.onsuccess = function (e) {

      var checkSetupComplete = function () {
        if (blobSupport === null || docCount === null ||
            instanceId === null) {
          return;
        } else {
          api._meta = {
            name: dbName,
            instanceId: instanceId,
            blobSupport: blobSupport,
            docCount: docCount
          };

          cachedDBs.set(dbName, {
            idb: idb,
            global: api._meta
          });
          callback(null, api);
        }
      };

      //
      // fetch/store the id
      //

      var meta = e.target.result || {id: META_STORE};
      if (dbName  + '_id' in meta) {
        instanceId = meta[dbName + '_id'];
        checkSetupComplete();
      } else {
        instanceId = uuid();
        meta[dbName + '_id'] = instanceId;
        txn.objectStore(META_STORE).put(meta).onsuccess = function () {
          checkSetupComplete();
        };
      }

      //
      // check blob support
      //

      if (!blobSupportPromise) {
        // make sure blob support is only checked once
        blobSupportPromise = checkBlobSupport(txn);
      }

      blobSupportPromise.then(function (val) {
        blobSupport = val;
        checkSetupComplete();
      });

      //
      // count docs
      //

      var index = txn.objectStore(DOC_STORE).index('deletedOrLocal');
      index.count(IDBKeyRange.only('0')).onsuccess = function (e) {
        docCount = e.target.result;
        checkSetupComplete();
      };

    };
  };

  req.onerror = function () {
    var msg = 'Failed to open indexedDB, are you in private browsing mode?';
    guardedConsole('error', msg);
    callback(createError(IDB_ERROR, msg));
  };
}

IdbPouch.valid = function () {
  // Issue #2533, we finally gave up on doing bug
  // detection instead of browser sniffing. Safari brought us
  // to our knees.
  var isSafari = typeof openDatabase !== 'undefined' &&
    /(Safari|iPhone|iPad|iPod)/.test(navigator.userAgent) &&
    !/Chrome/.test(navigator.userAgent) &&
    !/BlackBerry/.test(navigator.platform);

  // some outdated implementations of IDB that appear on Samsung
  // and HTC Android devices <4.4 are missing IDBKeyRange
  return !isSafari && typeof indexedDB !== 'undefined' &&
    typeof IDBKeyRange !== 'undefined';
};

function tryStorageOption(dbName, storage) {
  try { // option only available in Firefox 26+
    return indexedDB.open(dbName, {
      version: ADAPTER_VERSION,
      storage: storage
    });
  } catch(err) {
      return indexedDB.open(dbName, ADAPTER_VERSION);
  }
}

function IDBPouch (PouchDB) {
  PouchDB.adapter('idb', IdbPouch, true);
}

//
// Parsing hex strings. Yeah.
//
// So basically we need this because of a bug in WebSQL:
// https://code.google.com/p/chromium/issues/detail?id=422690
// https://bugs.webkit.org/show_bug.cgi?id=137637
//
// UTF-8 and UTF-16 are provided as separate functions
// for meager performance improvements
//

function decodeUtf8(str) {
  return decodeURIComponent(escape(str));
}

function hexToInt(charCode) {
  // '0'-'9' is 48-57
  // 'A'-'F' is 65-70
  // SQLite will only give us uppercase hex
  return charCode < 65 ? (charCode - 48) : (charCode - 55);
}


// Example:
// pragma encoding=utf8;
// select hex('A');
// returns '41'
function parseHexUtf8(str, start, end) {
  var result = '';
  while (start < end) {
    result += String.fromCharCode(
      (hexToInt(str.charCodeAt(start++)) << 4) |
        hexToInt(str.charCodeAt(start++)));
  }
  return result;
}

// Example:
// pragma encoding=utf16;
// select hex('A');
// returns '4100'
// notice that the 00 comes after the 41 (i.e. it's swizzled)
function parseHexUtf16(str, start, end) {
  var result = '';
  while (start < end) {
    // UTF-16, so swizzle the bytes
    result += String.fromCharCode(
      (hexToInt(str.charCodeAt(start + 2)) << 12) |
        (hexToInt(str.charCodeAt(start + 3)) << 8) |
        (hexToInt(str.charCodeAt(start)) << 4) |
        hexToInt(str.charCodeAt(start + 1)));
    start += 4;
  }
  return result;
}

function parseHexString(str, encoding) {
  if (encoding === 'UTF-8') {
    return decodeUtf8(parseHexUtf8(str, 0, str.length));
  } else {
    return parseHexUtf16(str, 0, str.length);
  }
}

function quote(str) {
  return "'" + str + "'";
}

var ADAPTER_VERSION$1 = 7; // used to manage migrations

// The object stores created for each database
// DOC_STORE stores the document meta data, its revision history and state
var DOC_STORE$1 = quote('document-store');
// BY_SEQ_STORE stores a particular version of a document, keyed by its
// sequence id
var BY_SEQ_STORE$1 = quote('by-sequence');
// Where we store attachments
var ATTACH_STORE$1 = quote('attach-store');
var LOCAL_STORE$1 = quote('local-store');
var META_STORE$1 = quote('metadata-store');
// where we store many-to-many relations between attachment
// digests and seqs
var ATTACH_AND_SEQ_STORE$1 = quote('attach-seq-store');

// escapeBlob and unescapeBlob are workarounds for a websql bug:
// https://code.google.com/p/chromium/issues/detail?id=422690
// https://bugs.webkit.org/show_bug.cgi?id=137637
// The goal is to never actually insert the \u0000 character
// in the database.
function escapeBlob(str) {
  return str
    .replace(/\u0002/g, '\u0002\u0002')
    .replace(/\u0001/g, '\u0001\u0002')
    .replace(/\u0000/g, '\u0001\u0001');
}

function unescapeBlob(str) {
  return str
    .replace(/\u0001\u0001/g, '\u0000')
    .replace(/\u0001\u0002/g, '\u0001')
    .replace(/\u0002\u0002/g, '\u0002');
}

function stringifyDoc(doc) {
  // don't bother storing the id/rev. it uses lots of space,
  // in persistent map/reduce especially
  delete doc._id;
  delete doc._rev;
  return JSON.stringify(doc);
}

function unstringifyDoc(doc, id, rev) {
  doc = JSON.parse(doc);
  doc._id = id;
  doc._rev = rev;
  return doc;
}

// question mark groups IN queries, e.g. 3 -> '(?,?,?)'
function qMarks(num) {
  var s = '(';
  while (num--) {
    s += '?';
    if (num) {
      s += ',';
    }
  }
  return s + ')';
}

function select(selector, table, joiner, where, orderBy) {
  return 'SELECT ' + selector + ' FROM ' +
    (typeof table === 'string' ? table : table.join(' JOIN ')) +
    (joiner ? (' ON ' + joiner) : '') +
    (where ? (' WHERE ' +
    (typeof where === 'string' ? where : where.join(' AND '))) : '') +
    (orderBy ? (' ORDER BY ' + orderBy) : '');
}

function compactRevs$1(revs, docId, tx) {

  if (!revs.length) {
    return;
  }

  var numDone = 0;
  var seqs = [];

  function checkDone() {
    if (++numDone === revs.length) { // done
      deleteOrphans();
    }
  }

  function deleteOrphans() {
    // find orphaned attachment digests

    if (!seqs.length) {
      return;
    }

    var sql = 'SELECT DISTINCT digest AS digest FROM ' +
      ATTACH_AND_SEQ_STORE$1 + ' WHERE seq IN ' + qMarks(seqs.length);

    tx.executeSql(sql, seqs, function (tx, res) {

      var digestsToCheck = [];
      for (var i = 0; i < res.rows.length; i++) {
        digestsToCheck.push(res.rows.item(i).digest);
      }
      if (!digestsToCheck.length) {
        return;
      }

      var sql = 'DELETE FROM ' + ATTACH_AND_SEQ_STORE$1 +
        ' WHERE seq IN (' +
        seqs.map(function () { return '?'; }).join(',') +
        ')';
      tx.executeSql(sql, seqs, function (tx) {

        var sql = 'SELECT digest FROM ' + ATTACH_AND_SEQ_STORE$1 +
          ' WHERE digest IN (' +
          digestsToCheck.map(function () { return '?'; }).join(',') +
          ')';
        tx.executeSql(sql, digestsToCheck, function (tx, res) {
          var nonOrphanedDigests = new _Set();
          for (var i = 0; i < res.rows.length; i++) {
            nonOrphanedDigests.add(res.rows.item(i).digest);
          }
          digestsToCheck.forEach(function (digest) {
            if (nonOrphanedDigests.has(digest)) {
              return;
            }
            tx.executeSql(
              'DELETE FROM ' + ATTACH_AND_SEQ_STORE$1 + ' WHERE digest=?',
              [digest]);
            tx.executeSql(
              'DELETE FROM ' + ATTACH_STORE$1 + ' WHERE digest=?', [digest]);
          });
        });
      });
    });
  }

  // update by-seq and attach stores in parallel
  revs.forEach(function (rev) {
    var sql = 'SELECT seq FROM ' + BY_SEQ_STORE$1 +
      ' WHERE doc_id=? AND rev=?';

    tx.executeSql(sql, [docId, rev], function (tx, res) {
      if (!res.rows.length) { // already deleted
        return checkDone();
      }
      var seq = res.rows.item(0).seq;
      seqs.push(seq);

      tx.executeSql(
        'DELETE FROM ' + BY_SEQ_STORE$1 + ' WHERE seq=?', [seq], checkDone);
    });
  });
}

function websqlError(callback) {
  return function (event) {
    guardedConsole('error', 'WebSQL threw an error', event);
    // event may actually be a SQLError object, so report is as such
    var errorNameMatch = event && event.constructor.toString()
        .match(/function ([^\(]+)/);
    var errorName = (errorNameMatch && errorNameMatch[1]) || event.type;
    var errorReason = event.target || event.message;
    callback(createError(WSQ_ERROR, errorReason, errorName));
  };
}

function getSize(opts) {
  if ('size' in opts) {
    // triggers immediate popup in iOS, fixes #2347
    // e.g. 5000001 asks for 5 MB, 10000001 asks for 10 MB,
    return opts.size * 1000000;
  }
  // In iOS, doesn't matter as long as it's <= 5000000.
  // Except that if you request too much, our tests fail
  // because of the native "do you accept?" popup.
  // In Android <=4.3, this value is actually used as an
  // honest-to-god ceiling for data, so we need to
  // set it to a decently high number.
  var isAndroid = typeof navigator !== 'undefined' &&
    /Android/.test(navigator.userAgent);
  return isAndroid ? 5000000 : 1; // in PhantomJS, if you use 0 it will crash
}

function websqlBulkDocs(dbOpts, req, opts, api, db, websqlChanges, callback) {
  var newEdits = opts.new_edits;
  var userDocs = req.docs;

  // Parse the docs, give them a sequence number for the result
  var docInfos = userDocs.map(function (doc) {
    if (doc._id && isLocalId(doc._id)) {
      return doc;
    }
    var newDoc = parseDoc(doc, newEdits);
    return newDoc;
  });

  var docInfoErrors = docInfos.filter(function (docInfo) {
    return docInfo.error;
  });
  if (docInfoErrors.length) {
    return callback(docInfoErrors[0]);
  }

  var tx;
  var results = new Array(docInfos.length);
  var fetchedDocs = new _Map();

  var preconditionErrored;
  function complete() {
    if (preconditionErrored) {
      return callback(preconditionErrored);
    }
    websqlChanges.notify(api._name);
    api._docCount = -1; // invalidate
    callback(null, results);
  }

  function verifyAttachment(digest, callback) {
    var sql = 'SELECT count(*) as cnt FROM ' + ATTACH_STORE$1 +
      ' WHERE digest=?';
    tx.executeSql(sql, [digest], function (tx, result) {
      if (result.rows.item(0).cnt === 0) {
        var err = createError(MISSING_STUB,
          'unknown stub attachment with digest ' +
          digest);
        callback(err);
      } else {
        callback();
      }
    });
  }

  function verifyAttachments(finish) {
    var digests = [];
    docInfos.forEach(function (docInfo) {
      if (docInfo.data && docInfo.data._attachments) {
        Object.keys(docInfo.data._attachments).forEach(function (filename) {
          var att = docInfo.data._attachments[filename];
          if (att.stub) {
            digests.push(att.digest);
          }
        });
      }
    });
    if (!digests.length) {
      return finish();
    }
    var numDone = 0;
    var err;

    function checkDone() {
      if (++numDone === digests.length) {
        finish(err);
      }
    }
    digests.forEach(function (digest) {
      verifyAttachment(digest, function (attErr) {
        if (attErr && !err) {
          err = attErr;
        }
        checkDone();
      });
    });
  }

  function writeDoc(docInfo, winningRev, winningRevIsDeleted, newRevIsDeleted,
                    isUpdate, delta, resultsIdx, callback) {

    function finish() {
      var data = docInfo.data;
      var deletedInt = newRevIsDeleted ? 1 : 0;

      var id = data._id;
      var rev = data._rev;
      var json = stringifyDoc(data);
      var sql = 'INSERT INTO ' + BY_SEQ_STORE$1 +
        ' (doc_id, rev, json, deleted) VALUES (?, ?, ?, ?);';
      var sqlArgs = [id, rev, json, deletedInt];

      // map seqs to attachment digests, which
      // we will need later during compaction
      function insertAttachmentMappings(seq, callback) {
        var attsAdded = 0;
        var attsToAdd = Object.keys(data._attachments || {});

        if (!attsToAdd.length) {
          return callback();
        }
        function checkDone() {
          if (++attsAdded === attsToAdd.length) {
            callback();
          }
          return false; // ack handling a constraint error
        }
        function add(att) {
          var sql = 'INSERT INTO ' + ATTACH_AND_SEQ_STORE$1 +
            ' (digest, seq) VALUES (?,?)';
          var sqlArgs = [data._attachments[att].digest, seq];
          tx.executeSql(sql, sqlArgs, checkDone, checkDone);
          // second callback is for a constaint error, which we ignore
          // because this docid/rev has already been associated with
          // the digest (e.g. when new_edits == false)
        }
        for (var i = 0; i < attsToAdd.length; i++) {
          add(attsToAdd[i]); // do in parallel
        }
      }

      tx.executeSql(sql, sqlArgs, function (tx, result) {
        var seq = result.insertId;
        insertAttachmentMappings(seq, function () {
          dataWritten(tx, seq);
        });
      }, function () {
        // constraint error, recover by updating instead (see #1638)
        var fetchSql = select('seq', BY_SEQ_STORE$1, null,
          'doc_id=? AND rev=?');
        tx.executeSql(fetchSql, [id, rev], function (tx, res) {
          var seq = res.rows.item(0).seq;
          var sql = 'UPDATE ' + BY_SEQ_STORE$1 +
            ' SET json=?, deleted=? WHERE doc_id=? AND rev=?;';
          var sqlArgs = [json, deletedInt, id, rev];
          tx.executeSql(sql, sqlArgs, function (tx) {
            insertAttachmentMappings(seq, function () {
              dataWritten(tx, seq);
            });
          });
        });
        return false; // ack that we've handled the error
      });
    }

    function collectResults(attachmentErr) {
      if (!err) {
        if (attachmentErr) {
          err = attachmentErr;
          callback(err);
        } else if (recv === attachments.length) {
          finish();
        }
      }
    }

    var err = null;
    var recv = 0;

    docInfo.data._id = docInfo.metadata.id;
    docInfo.data._rev = docInfo.metadata.rev;
    var attachments = Object.keys(docInfo.data._attachments || {});


    if (newRevIsDeleted) {
      docInfo.data._deleted = true;
    }

    function attachmentSaved(err) {
      recv++;
      collectResults(err);
    }

    attachments.forEach(function (key) {
      var att = docInfo.data._attachments[key];
      if (!att.stub) {
        var data = att.data;
        delete att.data;
        att.revpos = parseInt(winningRev, 10);
        var digest = att.digest;
        saveAttachment(digest, data, attachmentSaved);
      } else {
        recv++;
        collectResults();
      }
    });

    if (!attachments.length) {
      finish();
    }

    function dataWritten(tx, seq) {
      var id = docInfo.metadata.id;

      var revsToCompact = docInfo.stemmedRevs || [];
      if (isUpdate && api.auto_compaction) {
        revsToCompact = compactTree(docInfo.metadata).concat(revsToCompact);
      }
      if (revsToCompact.length) {
        compactRevs$1(revsToCompact, id, tx);
      }

      docInfo.metadata.seq = seq;
      delete docInfo.metadata.rev;

      var sql = isUpdate ?
      'UPDATE ' + DOC_STORE$1 +
      ' SET json=?, max_seq=?, winningseq=' +
      '(SELECT seq FROM ' + BY_SEQ_STORE$1 +
      ' WHERE doc_id=' + DOC_STORE$1 + '.id AND rev=?) WHERE id=?'
        : 'INSERT INTO ' + DOC_STORE$1 +
      ' (id, winningseq, max_seq, json) VALUES (?,?,?,?);';
      var metadataStr = safeJsonStringify(docInfo.metadata);
      var params = isUpdate ?
        [metadataStr, seq, winningRev, id] :
        [id, seq, seq, metadataStr];
      tx.executeSql(sql, params, function () {
        results[resultsIdx] = {
          ok: true,
          id: docInfo.metadata.id,
          rev: winningRev
        };
        fetchedDocs.set(id, docInfo.metadata);
        callback();
      });
    }
  }

  function websqlProcessDocs() {
    processDocs(dbOpts.revs_limit, docInfos, api, fetchedDocs, tx,
                results, writeDoc, opts);
  }

  function fetchExistingDocs(callback) {
    if (!docInfos.length) {
      return callback();
    }

    var numFetched = 0;

    function checkDone() {
      if (++numFetched === docInfos.length) {
        callback();
      }
    }

    docInfos.forEach(function (docInfo) {
      if (docInfo._id && isLocalId(docInfo._id)) {
        return checkDone(); // skip local docs
      }
      var id = docInfo.metadata.id;
      tx.executeSql('SELECT json FROM ' + DOC_STORE$1 +
      ' WHERE id = ?', [id], function (tx, result) {
        if (result.rows.length) {
          var metadata = safeJsonParse(result.rows.item(0).json);
          fetchedDocs.set(id, metadata);
        }
        checkDone();
      });
    });
  }

  function saveAttachment(digest, data, callback) {
    var sql = 'SELECT digest FROM ' + ATTACH_STORE$1 + ' WHERE digest=?';
    tx.executeSql(sql, [digest], function (tx, result) {
      if (result.rows.length) { // attachment already exists
        return callback();
      }
      // we could just insert before selecting and catch the error,
      // but my hunch is that it's cheaper not to serialize the blob
      // from JS to C if we don't have to (TODO: confirm this)
      sql = 'INSERT INTO ' + ATTACH_STORE$1 +
      ' (digest, body, escaped) VALUES (?,?,1)';
      tx.executeSql(sql, [digest, escapeBlob(data)], function () {
        callback();
      }, function () {
        // ignore constaint errors, means it already exists
        callback();
        return false; // ack we handled the error
      });
    });
  }

  preprocessAttachments(docInfos, 'binary', function (err) {
    if (err) {
      return callback(err);
    }
    db.transaction(function (txn) {
      tx = txn;
      verifyAttachments(function (err) {
        if (err) {
          preconditionErrored = err;
        } else {
          fetchExistingDocs(websqlProcessDocs);
        }
      });
    }, websqlError(callback), complete);
  });
}

var cachedDatabases = new _Map();

// openDatabase passed in through opts (e.g. for node-websql)
function openDatabaseWithOpts(opts) {
  return opts.websql(opts.name, opts.version, opts.description, opts.size);
}

function openDBSafely(opts) {
  try {
    return {
      db: openDatabaseWithOpts(opts)
    };
  } catch (err) {
    return {
      error: err
    };
  }
}

function openDB$1(opts) {
  var cachedResult = cachedDatabases.get(opts.name);
  if (!cachedResult) {
    cachedResult = openDBSafely(opts);
    cachedDatabases.set(opts.name, cachedResult);
  }
  return cachedResult;
}

var websqlChanges = new Changes();

function fetchAttachmentsIfNecessary$1(doc, opts, api, txn, cb) {
  var attachments = Object.keys(doc._attachments || {});
  if (!attachments.length) {
    return cb && cb();
  }
  var numDone = 0;

  function checkDone() {
    if (++numDone === attachments.length && cb) {
      cb();
    }
  }

  function fetchAttachment(doc, att) {
    var attObj = doc._attachments[att];
    var attOpts = {binary: opts.binary, ctx: txn};
    api._getAttachment(doc._id, att, attObj, attOpts, function (_, data) {
      doc._attachments[att] = extend$1(
        pick(attObj, ['digest', 'content_type']),
        { data: data }
      );
      checkDone();
    });
  }

  attachments.forEach(function (att) {
    if (opts.attachments && opts.include_docs) {
      fetchAttachment(doc, att);
    } else {
      doc._attachments[att].stub = true;
      checkDone();
    }
  });
}

var POUCH_VERSION = 1;

// these indexes cover the ground for most allDocs queries
var BY_SEQ_STORE_DELETED_INDEX_SQL =
  'CREATE INDEX IF NOT EXISTS \'by-seq-deleted-idx\' ON ' +
  BY_SEQ_STORE$1 + ' (seq, deleted)';
var BY_SEQ_STORE_DOC_ID_REV_INDEX_SQL =
  'CREATE UNIQUE INDEX IF NOT EXISTS \'by-seq-doc-id-rev\' ON ' +
    BY_SEQ_STORE$1 + ' (doc_id, rev)';
var DOC_STORE_WINNINGSEQ_INDEX_SQL =
  'CREATE INDEX IF NOT EXISTS \'doc-winningseq-idx\' ON ' +
  DOC_STORE$1 + ' (winningseq)';
var ATTACH_AND_SEQ_STORE_SEQ_INDEX_SQL =
  'CREATE INDEX IF NOT EXISTS \'attach-seq-seq-idx\' ON ' +
    ATTACH_AND_SEQ_STORE$1 + ' (seq)';
var ATTACH_AND_SEQ_STORE_ATTACH_INDEX_SQL =
  'CREATE UNIQUE INDEX IF NOT EXISTS \'attach-seq-digest-idx\' ON ' +
    ATTACH_AND_SEQ_STORE$1 + ' (digest, seq)';

var DOC_STORE_AND_BY_SEQ_JOINER = BY_SEQ_STORE$1 +
  '.seq = ' + DOC_STORE$1 + '.winningseq';

var SELECT_DOCS = BY_SEQ_STORE$1 + '.seq AS seq, ' +
  BY_SEQ_STORE$1 + '.deleted AS deleted, ' +
  BY_SEQ_STORE$1 + '.json AS data, ' +
  BY_SEQ_STORE$1 + '.rev AS rev, ' +
  DOC_STORE$1 + '.json AS metadata';

function WebSqlPouch$1(opts, callback) {
  var api = this;
  var instanceId = null;
  var size = getSize(opts);
  var idRequests = [];
  var encoding;

  api._docCount = -1; // cache sqlite count(*) for performance
  api._name = opts.name;

  // extend the options here, because sqlite plugin has a ton of options
  // and they are constantly changing, so it's more prudent to allow anything
  var websqlOpts = extend$1({}, opts, {
    version: POUCH_VERSION,
    description: opts.name,
    size: size
  });
  var openDBResult = openDB$1(websqlOpts);
  if (openDBResult.error) {
    return websqlError(callback)(openDBResult.error);
  }
  var db = openDBResult.db;
  if (typeof db.readTransaction !== 'function') {
    // doesn't exist in sqlite plugin
    db.readTransaction = db.transaction;
  }

  function dbCreated() {
    // note the db name in case the browser upgrades to idb
    if (hasLocalStorage()) {
      window.localStorage['_pouch__websqldb_' + api._name] = true;
    }
    callback(null, api);
  }

  // In this migration, we added the 'deleted' and 'local' columns to the
  // by-seq and doc store tables.
  // To preserve existing user data, we re-process all the existing JSON
  // and add these values.
  // Called migration2 because it corresponds to adapter version (db_version) #2
  function runMigration2(tx, callback) {
    // index used for the join in the allDocs query
    tx.executeSql(DOC_STORE_WINNINGSEQ_INDEX_SQL);

    tx.executeSql('ALTER TABLE ' + BY_SEQ_STORE$1 +
      ' ADD COLUMN deleted TINYINT(1) DEFAULT 0', [], function () {
      tx.executeSql(BY_SEQ_STORE_DELETED_INDEX_SQL);
      tx.executeSql('ALTER TABLE ' + DOC_STORE$1 +
        ' ADD COLUMN local TINYINT(1) DEFAULT 0', [], function () {
        tx.executeSql('CREATE INDEX IF NOT EXISTS \'doc-store-local-idx\' ON ' +
          DOC_STORE$1 + ' (local, id)');

        var sql = 'SELECT ' + DOC_STORE$1 + '.winningseq AS seq, ' + DOC_STORE$1 +
          '.json AS metadata FROM ' + BY_SEQ_STORE$1 + ' JOIN ' + DOC_STORE$1 +
          ' ON ' + BY_SEQ_STORE$1 + '.seq = ' + DOC_STORE$1 + '.winningseq';

        tx.executeSql(sql, [], function (tx, result) {

          var deleted = [];
          var local = [];

          for (var i = 0; i < result.rows.length; i++) {
            var item = result.rows.item(i);
            var seq = item.seq;
            var metadata = JSON.parse(item.metadata);
            if (isDeleted(metadata)) {
              deleted.push(seq);
            }
            if (isLocalId(metadata.id)) {
              local.push(metadata.id);
            }
          }
          tx.executeSql('UPDATE ' + DOC_STORE$1 + 'SET local = 1 WHERE id IN ' +
            qMarks(local.length), local, function () {
            tx.executeSql('UPDATE ' + BY_SEQ_STORE$1 +
              ' SET deleted = 1 WHERE seq IN ' +
              qMarks(deleted.length), deleted, callback);
          });
        });
      });
    });
  }

  // in this migration, we make all the local docs unversioned
  function runMigration3(tx, callback) {
    var local = 'CREATE TABLE IF NOT EXISTS ' + LOCAL_STORE$1 +
      ' (id UNIQUE, rev, json)';
    tx.executeSql(local, [], function () {
      var sql = 'SELECT ' + DOC_STORE$1 + '.id AS id, ' +
        BY_SEQ_STORE$1 + '.json AS data ' +
        'FROM ' + BY_SEQ_STORE$1 + ' JOIN ' +
        DOC_STORE$1 + ' ON ' + BY_SEQ_STORE$1 + '.seq = ' +
        DOC_STORE$1 + '.winningseq WHERE local = 1';
      tx.executeSql(sql, [], function (tx, res) {
        var rows = [];
        for (var i = 0; i < res.rows.length; i++) {
          rows.push(res.rows.item(i));
        }
        function doNext() {
          if (!rows.length) {
            return callback(tx);
          }
          var row = rows.shift();
          var rev = JSON.parse(row.data)._rev;
          tx.executeSql('INSERT INTO ' + LOCAL_STORE$1 +
              ' (id, rev, json) VALUES (?,?,?)',
              [row.id, rev, row.data], function (tx) {
            tx.executeSql('DELETE FROM ' + DOC_STORE$1 + ' WHERE id=?',
                [row.id], function (tx) {
              tx.executeSql('DELETE FROM ' + BY_SEQ_STORE$1 + ' WHERE seq=?',
                  [row.seq], function () {
                doNext();
              });
            });
          });
        }
        doNext();
      });
    });
  }

  // in this migration, we remove doc_id_rev and just use rev
  function runMigration4(tx, callback) {

    function updateRows(rows) {
      function doNext() {
        if (!rows.length) {
          return callback(tx);
        }
        var row = rows.shift();
        var doc_id_rev = parseHexString(row.hex, encoding);
        var idx = doc_id_rev.lastIndexOf('::');
        var doc_id = doc_id_rev.substring(0, idx);
        var rev = doc_id_rev.substring(idx + 2);
        var sql = 'UPDATE ' + BY_SEQ_STORE$1 +
          ' SET doc_id=?, rev=? WHERE doc_id_rev=?';
        tx.executeSql(sql, [doc_id, rev, doc_id_rev], function () {
          doNext();
        });
      }
      doNext();
    }

    var sql = 'ALTER TABLE ' + BY_SEQ_STORE$1 + ' ADD COLUMN doc_id';
    tx.executeSql(sql, [], function (tx) {
      var sql = 'ALTER TABLE ' + BY_SEQ_STORE$1 + ' ADD COLUMN rev';
      tx.executeSql(sql, [], function (tx) {
        tx.executeSql(BY_SEQ_STORE_DOC_ID_REV_INDEX_SQL, [], function (tx) {
          var sql = 'SELECT hex(doc_id_rev) as hex FROM ' + BY_SEQ_STORE$1;
          tx.executeSql(sql, [], function (tx, res) {
            var rows = [];
            for (var i = 0; i < res.rows.length; i++) {
              rows.push(res.rows.item(i));
            }
            updateRows(rows);
          });
        });
      });
    });
  }

  // in this migration, we add the attach_and_seq table
  // for issue #2818
  function runMigration5(tx, callback) {

    function migrateAttsAndSeqs(tx) {
      // need to actually populate the table. this is the expensive part,
      // so as an optimization, check first that this database even
      // contains attachments
      var sql = 'SELECT COUNT(*) AS cnt FROM ' + ATTACH_STORE$1;
      tx.executeSql(sql, [], function (tx, res) {
        var count = res.rows.item(0).cnt;
        if (!count) {
          return callback(tx);
        }

        var offset = 0;
        var pageSize = 10;
        function nextPage() {
          var sql = select(
            SELECT_DOCS + ', ' + DOC_STORE$1 + '.id AS id',
            [DOC_STORE$1, BY_SEQ_STORE$1],
            DOC_STORE_AND_BY_SEQ_JOINER,
            null,
            DOC_STORE$1 + '.id '
          );
          sql += ' LIMIT ' + pageSize + ' OFFSET ' + offset;
          offset += pageSize;
          tx.executeSql(sql, [], function (tx, res) {
            if (!res.rows.length) {
              return callback(tx);
            }
            var digestSeqs = {};
            function addDigestSeq(digest, seq) {
              // uniq digest/seq pairs, just in case there are dups
              var seqs = digestSeqs[digest] = (digestSeqs[digest] || []);
              if (seqs.indexOf(seq) === -1) {
                seqs.push(seq);
              }
            }
            for (var i = 0; i < res.rows.length; i++) {
              var row = res.rows.item(i);
              var doc = unstringifyDoc(row.data, row.id, row.rev);
              var atts = Object.keys(doc._attachments || {});
              for (var j = 0; j < atts.length; j++) {
                var att = doc._attachments[atts[j]];
                addDigestSeq(att.digest, row.seq);
              }
            }
            var digestSeqPairs = [];
            Object.keys(digestSeqs).forEach(function (digest) {
              var seqs = digestSeqs[digest];
              seqs.forEach(function (seq) {
                digestSeqPairs.push([digest, seq]);
              });
            });
            if (!digestSeqPairs.length) {
              return nextPage();
            }
            var numDone = 0;
            digestSeqPairs.forEach(function (pair) {
              var sql = 'INSERT INTO ' + ATTACH_AND_SEQ_STORE$1 +
                ' (digest, seq) VALUES (?,?)';
              tx.executeSql(sql, pair, function () {
                if (++numDone === digestSeqPairs.length) {
                  nextPage();
                }
              });
            });
          });
        }
        nextPage();
      });
    }

    var attachAndRev = 'CREATE TABLE IF NOT EXISTS ' +
      ATTACH_AND_SEQ_STORE$1 + ' (digest, seq INTEGER)';
    tx.executeSql(attachAndRev, [], function (tx) {
      tx.executeSql(
        ATTACH_AND_SEQ_STORE_ATTACH_INDEX_SQL, [], function (tx) {
          tx.executeSql(
            ATTACH_AND_SEQ_STORE_SEQ_INDEX_SQL, [],
            migrateAttsAndSeqs);
        });
    });
  }

  // in this migration, we use escapeBlob() and unescapeBlob()
  // instead of reading out the binary as HEX, which is slow
  function runMigration6(tx, callback) {
    var sql = 'ALTER TABLE ' + ATTACH_STORE$1 +
      ' ADD COLUMN escaped TINYINT(1) DEFAULT 0';
    tx.executeSql(sql, [], callback);
  }

  // issue #3136, in this migration we need a "latest seq" as well
  // as the "winning seq" in the doc store
  function runMigration7(tx, callback) {
    var sql = 'ALTER TABLE ' + DOC_STORE$1 +
      ' ADD COLUMN max_seq INTEGER';
    tx.executeSql(sql, [], function (tx) {
      var sql = 'UPDATE ' + DOC_STORE$1 + ' SET max_seq=(SELECT MAX(seq) FROM ' +
        BY_SEQ_STORE$1 + ' WHERE doc_id=id)';
      tx.executeSql(sql, [], function (tx) {
        // add unique index after filling, else we'll get a constraint
        // error when we do the ALTER TABLE
        var sql =
          'CREATE UNIQUE INDEX IF NOT EXISTS \'doc-max-seq-idx\' ON ' +
          DOC_STORE$1 + ' (max_seq)';
        tx.executeSql(sql, [], callback);
      });
    });
  }

  function checkEncoding(tx, cb) {
    // UTF-8 on chrome/android, UTF-16 on safari < 7.1
    tx.executeSql('SELECT HEX("a") AS hex', [], function (tx, res) {
        var hex = res.rows.item(0).hex;
        encoding = hex.length === 2 ? 'UTF-8' : 'UTF-16';
        cb();
      }
    );
  }

  function onGetInstanceId() {
    while (idRequests.length > 0) {
      var idCallback = idRequests.pop();
      idCallback(null, instanceId);
    }
  }

  function onGetVersion(tx, dbVersion) {
    if (dbVersion === 0) {
      // initial schema

      var meta = 'CREATE TABLE IF NOT EXISTS ' + META_STORE$1 +
        ' (dbid, db_version INTEGER)';
      var attach = 'CREATE TABLE IF NOT EXISTS ' + ATTACH_STORE$1 +
        ' (digest UNIQUE, escaped TINYINT(1), body BLOB)';
      var attachAndRev = 'CREATE TABLE IF NOT EXISTS ' +
        ATTACH_AND_SEQ_STORE$1 + ' (digest, seq INTEGER)';
      // TODO: migrate winningseq to INTEGER
      var doc = 'CREATE TABLE IF NOT EXISTS ' + DOC_STORE$1 +
        ' (id unique, json, winningseq, max_seq INTEGER UNIQUE)';
      var seq = 'CREATE TABLE IF NOT EXISTS ' + BY_SEQ_STORE$1 +
        ' (seq INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, ' +
        'json, deleted TINYINT(1), doc_id, rev)';
      var local = 'CREATE TABLE IF NOT EXISTS ' + LOCAL_STORE$1 +
        ' (id UNIQUE, rev, json)';

      // creates
      tx.executeSql(attach);
      tx.executeSql(local);
      tx.executeSql(attachAndRev, [], function () {
        tx.executeSql(ATTACH_AND_SEQ_STORE_SEQ_INDEX_SQL);
        tx.executeSql(ATTACH_AND_SEQ_STORE_ATTACH_INDEX_SQL);
      });
      tx.executeSql(doc, [], function () {
        tx.executeSql(DOC_STORE_WINNINGSEQ_INDEX_SQL);
        tx.executeSql(seq, [], function () {
          tx.executeSql(BY_SEQ_STORE_DELETED_INDEX_SQL);
          tx.executeSql(BY_SEQ_STORE_DOC_ID_REV_INDEX_SQL);
          tx.executeSql(meta, [], function () {
            // mark the db version, and new dbid
            var initSeq = 'INSERT INTO ' + META_STORE$1 +
              ' (db_version, dbid) VALUES (?,?)';
            instanceId = uuid();
            var initSeqArgs = [ADAPTER_VERSION$1, instanceId];
            tx.executeSql(initSeq, initSeqArgs, function () {
              onGetInstanceId();
            });
          });
        });
      });
    } else { // version > 0

      var setupDone = function () {
        var migrated = dbVersion < ADAPTER_VERSION$1;
        if (migrated) {
          // update the db version within this transaction
          tx.executeSql('UPDATE ' + META_STORE$1 + ' SET db_version = ' +
            ADAPTER_VERSION$1);
        }
        // notify db.id() callers
        var sql = 'SELECT dbid FROM ' + META_STORE$1;
        tx.executeSql(sql, [], function (tx, result) {
          instanceId = result.rows.item(0).dbid;
          onGetInstanceId();
        });
      };

      // would love to use promises here, but then websql
      // ends the transaction early
      var tasks = [
        runMigration2,
        runMigration3,
        runMigration4,
        runMigration5,
        runMigration6,
        runMigration7,
        setupDone
      ];

      // run each migration sequentially
      var i = dbVersion;
      var nextMigration = function (tx) {
        tasks[i - 1](tx, nextMigration);
        i++;
      };
      nextMigration(tx);
    }
  }

  function setup() {
    db.transaction(function (tx) {
      // first check the encoding
      checkEncoding(tx, function () {
        // then get the version
        fetchVersion(tx);
      });
    }, websqlError(callback), dbCreated);
  }

  function fetchVersion(tx) {
    var sql = 'SELECT sql FROM sqlite_master WHERE tbl_name = ' + META_STORE$1;
    tx.executeSql(sql, [], function (tx, result) {
      if (!result.rows.length) {
        // database hasn't even been created yet (version 0)
        onGetVersion(tx, 0);
      } else if (!/db_version/.test(result.rows.item(0).sql)) {
        // table was created, but without the new db_version column,
        // so add it.
        tx.executeSql('ALTER TABLE ' + META_STORE$1 +
          ' ADD COLUMN db_version INTEGER', [], function () {
          // before version 2, this column didn't even exist
          onGetVersion(tx, 1);
        });
      } else { // column exists, we can safely get it
        tx.executeSql('SELECT db_version FROM ' + META_STORE$1,
          [], function (tx, result) {
          var dbVersion = result.rows.item(0).db_version;
          onGetVersion(tx, dbVersion);
        });
      }
    });
  }

  setup();

  api.type = function () {
    return 'websql';
  };

  api._id = toPromise(function (callback) {
    callback(null, instanceId);
  });

  api._info = function (callback) {
    db.readTransaction(function (tx) {
      countDocs(tx, function (docCount) {
        var sql = 'SELECT MAX(seq) AS seq FROM ' + BY_SEQ_STORE$1;
        tx.executeSql(sql, [], function (tx, res) {
          var updateSeq = res.rows.item(0).seq || 0;
          callback(null, {
            doc_count: docCount,
            update_seq: updateSeq,
            websql_encoding: encoding
          });
        });
      });
    }, websqlError(callback));
  };

  api._bulkDocs = function (req, reqOpts, callback) {
    websqlBulkDocs(opts, req, reqOpts, api, db, websqlChanges, callback);
  };

  api._get = function (id, opts, callback) {
    var doc;
    var metadata;
    var err;
    var tx = opts.ctx;
    if (!tx) {
      return db.readTransaction(function (txn) {
        api._get(id, extend$1({ctx: txn}, opts), callback);
      });
    }

    function finish() {
      callback(err, {doc: doc, metadata: metadata, ctx: tx});
    }

    var sql;
    var sqlArgs;
    if (opts.rev) {
      sql = select(
        SELECT_DOCS,
        [DOC_STORE$1, BY_SEQ_STORE$1],
        DOC_STORE$1 + '.id=' + BY_SEQ_STORE$1 + '.doc_id',
        [BY_SEQ_STORE$1 + '.doc_id=?', BY_SEQ_STORE$1 + '.rev=?']);
      sqlArgs = [id, opts.rev];
    } else {
      sql = select(
        SELECT_DOCS,
        [DOC_STORE$1, BY_SEQ_STORE$1],
        DOC_STORE_AND_BY_SEQ_JOINER,
        DOC_STORE$1 + '.id=?');
      sqlArgs = [id];
    }
    tx.executeSql(sql, sqlArgs, function (a, results) {
      if (!results.rows.length) {
        err = createError(MISSING_DOC, 'missing');
        return finish();
      }
      var item = results.rows.item(0);
      metadata = safeJsonParse(item.metadata);
      if (item.deleted && !opts.rev) {
        err = createError(MISSING_DOC, 'deleted');
        return finish();
      }
      doc = unstringifyDoc(item.data, metadata.id, item.rev);
      finish();
    });
  };

  function countDocs(tx, callback) {

    if (api._docCount !== -1) {
      return callback(api._docCount);
    }

    // count the total rows
    var sql = select(
      'COUNT(' + DOC_STORE$1 + '.id) AS \'num\'',
      [DOC_STORE$1, BY_SEQ_STORE$1],
      DOC_STORE_AND_BY_SEQ_JOINER,
      BY_SEQ_STORE$1 + '.deleted=0');

    tx.executeSql(sql, [], function (tx, result) {
      api._docCount = result.rows.item(0).num;
      callback(api._docCount);
    });
  }

  api._allDocs = function (opts, callback) {
    var results = [];
    var totalRows;

    var start = 'startkey' in opts ? opts.startkey : false;
    var end = 'endkey' in opts ? opts.endkey : false;
    var key = 'key' in opts ? opts.key : false;
    var descending = 'descending' in opts ? opts.descending : false;
    var limit = 'limit' in opts ? opts.limit : -1;
    var offset = 'skip' in opts ? opts.skip : 0;
    var inclusiveEnd = opts.inclusive_end !== false;

    var sqlArgs = [];
    var criteria = [];

    if (key !== false) {
      criteria.push(DOC_STORE$1 + '.id = ?');
      sqlArgs.push(key);
    } else if (start !== false || end !== false) {
      if (start !== false) {
        criteria.push(DOC_STORE$1 + '.id ' + (descending ? '<=' : '>=') + ' ?');
        sqlArgs.push(start);
      }
      if (end !== false) {
        var comparator = descending ? '>' : '<';
        if (inclusiveEnd) {
          comparator += '=';
        }
        criteria.push(DOC_STORE$1 + '.id ' + comparator + ' ?');
        sqlArgs.push(end);
      }
      if (key !== false) {
        criteria.push(DOC_STORE$1 + '.id = ?');
        sqlArgs.push(key);
      }
    }

    if (opts.deleted !== 'ok') {
      // report deleted if keys are specified
      criteria.push(BY_SEQ_STORE$1 + '.deleted = 0');
    }

    db.readTransaction(function (tx) {

      // first count up the total rows
      countDocs(tx, function (count) {
        totalRows = count;

        if (limit === 0) {
          return;
        }

        // then actually fetch the documents
        var sql = select(
          SELECT_DOCS,
          [DOC_STORE$1, BY_SEQ_STORE$1],
          DOC_STORE_AND_BY_SEQ_JOINER,
          criteria,
          DOC_STORE$1 + '.id ' + (descending ? 'DESC' : 'ASC')
          );
        sql += ' LIMIT ' + limit + ' OFFSET ' + offset;

        tx.executeSql(sql, sqlArgs, function (tx, result) {
          for (var i = 0, l = result.rows.length; i < l; i++) {
            var item = result.rows.item(i);
            var metadata = safeJsonParse(item.metadata);
            var id = metadata.id;
            var data = unstringifyDoc(item.data, id, item.rev);
            var winningRev = data._rev;
            var doc = {
              id: id,
              key: id,
              value: {rev: winningRev}
            };
            if (opts.include_docs) {
              doc.doc = data;
              doc.doc._rev = winningRev;
              if (opts.conflicts) {
                doc.doc._conflicts = collectConflicts(metadata);
              }
              fetchAttachmentsIfNecessary$1(doc.doc, opts, api, tx);
            }
            if (item.deleted) {
              if (opts.deleted === 'ok') {
                doc.value.deleted = true;
                doc.doc = null;
              } else {
                continue;
              }
            }
            results.push(doc);
          }
        });
      });
    }, websqlError(callback), function () {
      callback(null, {
        total_rows: totalRows,
        offset: opts.skip,
        rows: results
      });
    });
  };

  api._changes = function (opts) {
    opts = clone(opts);

    if (opts.continuous) {
      var id = api._name + ':' + uuid();
      websqlChanges.addListener(api._name, id, api, opts);
      websqlChanges.notify(api._name);
      return {
        cancel: function () {
          websqlChanges.removeListener(api._name, id);
        }
      };
    }

    var descending = opts.descending;

    // Ignore the `since` parameter when `descending` is true
    opts.since = opts.since && !descending ? opts.since : 0;

    var limit = 'limit' in opts ? opts.limit : -1;
    if (limit === 0) {
      limit = 1; // per CouchDB _changes spec
    }

    var returnDocs;
    if ('return_docs' in opts) {
      returnDocs = opts.return_docs;
    } else if ('returnDocs' in opts) {
      // TODO: Remove 'returnDocs' in favor of 'return_docs' in a future release
      returnDocs = opts.returnDocs;
    } else {
      returnDocs = true;
    }
    var results = [];
    var numResults = 0;

    function fetchChanges() {

      var selectStmt =
        DOC_STORE$1 + '.json AS metadata, ' +
        DOC_STORE$1 + '.max_seq AS maxSeq, ' +
        BY_SEQ_STORE$1 + '.json AS winningDoc, ' +
        BY_SEQ_STORE$1 + '.rev AS winningRev ';

      var from = DOC_STORE$1 + ' JOIN ' + BY_SEQ_STORE$1;

      var joiner = DOC_STORE$1 + '.id=' + BY_SEQ_STORE$1 + '.doc_id' +
        ' AND ' + DOC_STORE$1 + '.winningseq=' + BY_SEQ_STORE$1 + '.seq';

      var criteria = ['maxSeq > ?'];
      var sqlArgs = [opts.since];

      if (opts.doc_ids) {
        criteria.push(DOC_STORE$1 + '.id IN ' + qMarks(opts.doc_ids.length));
        sqlArgs = sqlArgs.concat(opts.doc_ids);
      }

      var orderBy = 'maxSeq ' + (descending ? 'DESC' : 'ASC');

      var sql = select(selectStmt, from, joiner, criteria, orderBy);

      var filter = filterChange(opts);
      if (!opts.view && !opts.filter) {
        // we can just limit in the query
        sql += ' LIMIT ' + limit;
      }

      var lastSeq = opts.since || 0;
      db.readTransaction(function (tx) {
        tx.executeSql(sql, sqlArgs, function (tx, result) {
          function reportChange(change) {
            return function () {
              opts.onChange(change);
            };
          }
          for (var i = 0, l = result.rows.length; i < l; i++) {
            var item = result.rows.item(i);
            var metadata = safeJsonParse(item.metadata);
            lastSeq = item.maxSeq;

            var doc = unstringifyDoc(item.winningDoc, metadata.id,
              item.winningRev);
            var change = opts.processChange(doc, metadata, opts);
            change.seq = item.maxSeq;

            var filtered = filter(change);
            if (typeof filtered === 'object') {
              return opts.complete(filtered);
            }

            if (filtered) {
              numResults++;
              if (returnDocs) {
                results.push(change);
              }
              // process the attachment immediately
              // for the benefit of live listeners
              if (opts.attachments && opts.include_docs) {
                fetchAttachmentsIfNecessary$1(doc, opts, api, tx,
                  reportChange(change));
              } else {
                reportChange(change)();
              }
            }
            if (numResults === limit) {
              break;
            }
          }
        });
      }, websqlError(opts.complete), function () {
        if (!opts.continuous) {
          opts.complete(null, {
            results: results,
            last_seq: lastSeq
          });
        }
      });
    }

    fetchChanges();
  };

  api._close = function (callback) {
    //WebSQL databases do not need to be closed
    callback();
  };

  api._getAttachment = function (docId, attachId, attachment, opts, callback) {
    var res;
    var tx = opts.ctx;
    var digest = attachment.digest;
    var type = attachment.content_type;
    var sql = 'SELECT escaped, ' +
      'CASE WHEN escaped = 1 THEN body ELSE HEX(body) END AS body FROM ' +
      ATTACH_STORE$1 + ' WHERE digest=?';
    tx.executeSql(sql, [digest], function (tx, result) {
      // websql has a bug where \u0000 causes early truncation in strings
      // and blobs. to work around this, we used to use the hex() function,
      // but that's not performant. after migration 6, we remove \u0000
      // and add it back in afterwards
      var item = result.rows.item(0);
      var data = item.escaped ? unescapeBlob(item.body) :
        parseHexString(item.body, encoding);
      if (opts.binary) {
        res = binStringToBluffer(data, type);
      } else {
        res = btoa$1(data);
      }
      callback(null, res);
    });
  };

  api._getRevisionTree = function (docId, callback) {
    db.readTransaction(function (tx) {
      var sql = 'SELECT json AS metadata FROM ' + DOC_STORE$1 + ' WHERE id = ?';
      tx.executeSql(sql, [docId], function (tx, result) {
        if (!result.rows.length) {
          callback(createError(MISSING_DOC));
        } else {
          var data = safeJsonParse(result.rows.item(0).metadata);
          callback(null, data.rev_tree);
        }
      });
    });
  };

  api._doCompaction = function (docId, revs, callback) {
    if (!revs.length) {
      return callback();
    }
    db.transaction(function (tx) {

      // update doc store
      var sql = 'SELECT json AS metadata FROM ' + DOC_STORE$1 + ' WHERE id = ?';
      tx.executeSql(sql, [docId], function (tx, result) {
        var metadata = safeJsonParse(result.rows.item(0).metadata);
        traverseRevTree(metadata.rev_tree, function (isLeaf, pos,
                                                           revHash, ctx, opts) {
          var rev = pos + '-' + revHash;
          if (revs.indexOf(rev) !== -1) {
            opts.status = 'missing';
          }
        });

        var sql = 'UPDATE ' + DOC_STORE$1 + ' SET json = ? WHERE id = ?';
        tx.executeSql(sql, [safeJsonStringify(metadata), docId]);
      });

      compactRevs$1(revs, docId, tx);
    }, websqlError(callback), function () {
      callback();
    });
  };

  api._getLocal = function (id, callback) {
    db.readTransaction(function (tx) {
      var sql = 'SELECT json, rev FROM ' + LOCAL_STORE$1 + ' WHERE id=?';
      tx.executeSql(sql, [id], function (tx, res) {
        if (res.rows.length) {
          var item = res.rows.item(0);
          var doc = unstringifyDoc(item.json, id, item.rev);
          callback(null, doc);
        } else {
          callback(createError(MISSING_DOC));
        }
      });
    });
  };

  api._putLocal = function (doc, opts, callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    delete doc._revisions; // ignore this, trust the rev
    var oldRev = doc._rev;
    var id = doc._id;
    var newRev;
    if (!oldRev) {
      newRev = doc._rev = '0-1';
    } else {
      newRev = doc._rev = '0-' + (parseInt(oldRev.split('-')[1], 10) + 1);
    }
    var json = stringifyDoc(doc);

    var ret;
    function putLocal(tx) {
      var sql;
      var values;
      if (oldRev) {
        sql = 'UPDATE ' + LOCAL_STORE$1 + ' SET rev=?, json=? ' +
          'WHERE id=? AND rev=?';
        values = [newRev, json, id, oldRev];
      } else {
        sql = 'INSERT INTO ' + LOCAL_STORE$1 + ' (id, rev, json) VALUES (?,?,?)';
        values = [id, newRev, json];
      }
      tx.executeSql(sql, values, function (tx, res) {
        if (res.rowsAffected) {
          ret = {ok: true, id: id, rev: newRev};
          if (opts.ctx) { // return immediately
            callback(null, ret);
          }
        } else {
          callback(createError(REV_CONFLICT));
        }
      }, function () {
        callback(createError(REV_CONFLICT));
        return false; // ack that we handled the error
      });
    }

    if (opts.ctx) {
      putLocal(opts.ctx);
    } else {
      db.transaction(putLocal, websqlError(callback), function () {
        if (ret) {
          callback(null, ret);
        }
      });
    }
  };

  api._removeLocal = function (doc, opts, callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    var ret;

    function removeLocal(tx) {
      var sql = 'DELETE FROM ' + LOCAL_STORE$1 + ' WHERE id=? AND rev=?';
      var params = [doc._id, doc._rev];
      tx.executeSql(sql, params, function (tx, res) {
        if (!res.rowsAffected) {
          return callback(createError(MISSING_DOC));
        }
        ret = {ok: true, id: doc._id, rev: '0-0'};
        if (opts.ctx) { // return immediately
          callback(null, ret);
        }
      });
    }

    if (opts.ctx) {
      removeLocal(opts.ctx);
    } else {
      db.transaction(removeLocal, websqlError(callback), function () {
        if (ret) {
          callback(null, ret);
        }
      });
    }
  };

  api._destroy = function (opts, callback) {
    websqlChanges.removeAllListeners(api._name);
    db.transaction(function (tx) {
      var stores = [DOC_STORE$1, BY_SEQ_STORE$1, ATTACH_STORE$1, META_STORE$1,
        LOCAL_STORE$1, ATTACH_AND_SEQ_STORE$1];
      stores.forEach(function (store) {
        tx.executeSql('DROP TABLE IF EXISTS ' + store, []);
      });
    }, websqlError(callback), function () {
      if (hasLocalStorage()) {
        delete window.localStorage['_pouch__websqldb_' + api._name];
        delete window.localStorage[api._name];
      }
      callback(null, {'ok': true});
    });
  };
}

function canOpenTestDB() {
  try {
    openDatabase('_pouch_validate_websql', 1, '', 1);
    return true;
  } catch (err) {
    return false;
  }
}

// WKWebView had a bug where WebSQL would throw a DOM Exception 18
// (see https://bugs.webkit.org/show_bug.cgi?id=137760 and
// https://github.com/pouchdb/pouchdb/issues/5079)
// This has been fixed in latest WebKit, so we try to detect it here.
function isValidWebSQL() {
  // WKWebView UA:
  //   Mozilla/5.0 (iPhone; CPU iPhone OS 9_2 like Mac OS X)
  //   AppleWebKit/601.1.46 (KHTML, like Gecko) Mobile/13C75
  // Chrome for iOS UA:
  //   Mozilla/5.0 (iPhone; U; CPU iPhone OS 5_1_1 like Mac OS X; en)
  //   AppleWebKit/534.46.0 (KHTML, like Gecko) CriOS/19.0.1084.60
  //   Mobile/9B206 Safari/7534.48.3
  // Firefox for iOS UA:
  //   Mozilla/5.0 (iPhone; CPU iPhone OS 8_3 like Mac OS X) AppleWebKit/600.1.4
  //   (KHTML, like Gecko) FxiOS/1.0 Mobile/12F69 Safari/600.1.4

  // indexedDB is null on some UIWebViews and undefined in others
  // see: https://bugs.webkit.org/show_bug.cgi?id=137034
  if (typeof indexedDB === 'undefined' || indexedDB === null ||
      !/iP(hone|od|ad)/.test(navigator.userAgent)) {
    // definitely not WKWebView, avoid creating an unnecessary database
    return true;
  }
  // Cache the result in LocalStorage. Reason we do this is because if we
  // call openDatabase() too many times, Safari craps out in SauceLabs and
  // starts throwing DOM Exception 14s.
  var hasLS = hasLocalStorage();
  // Include user agent in the hash, so that if Safari is upgraded, we don't
  // continually think it's broken.
  var localStorageKey = '_pouch__websqldb_valid_' + navigator.userAgent;
  if (hasLS && localStorage[localStorageKey]) {
    return localStorage[localStorageKey] === '1';
  }
  var openedTestDB = canOpenTestDB();
  if (hasLS) {
    localStorage[localStorageKey] = openedTestDB ? '1' : '0';
  }
  return openedTestDB;
}

function valid() {
  if (typeof openDatabase !== 'function') {
    return false;
  }
  return isValidWebSQL();
}

function openDB(name, version, description, size) {
  // Traditional WebSQL API
  return openDatabase(name, version, description, size);
}

function WebSQLPouch(opts, callback) {
  var _opts = extend$1({
    websql: openDB
  }, opts);

  WebSqlPouch$1.call(this, _opts, callback);
}

WebSQLPouch.valid = valid;

WebSQLPouch.use_prefix = true;

function WebSqlPouch (PouchDB) {
  PouchDB.adapter('websql', WebSQLPouch, true);
}

/* global fetch */
/* global Headers */
function wrappedFetch() {
  var wrappedPromise = {};

  var promise = new PouchPromise(function (resolve, reject) {
    wrappedPromise.resolve = resolve;
    wrappedPromise.reject = reject;
  });

  var args = new Array(arguments.length);

  for (var i = 0; i < args.length; i++) {
    args[i] = arguments[i];
  }

  wrappedPromise.promise = promise;

  PouchPromise.resolve().then(function () {
    return fetch.apply(null, args);
  }).then(function (response) {
    wrappedPromise.resolve(response);
  }).catch(function (error) {
    wrappedPromise.reject(error);
  });

  return wrappedPromise;
}

function fetchRequest(options, callback) {
  var wrappedPromise, timer, response;

  var headers = new Headers();

  var fetchOptions = {
    method: options.method,
    credentials: 'include',
    headers: headers
  };

  if (options.json) {
    headers.set('Accept', 'application/json');
    headers.set('Content-Type', options.headers['Content-Type'] ||
      'application/json');
  }

  if (options.body && (options.body instanceof Blob)) {
    readAsArrayBuffer(options.body, function (arrayBuffer) {
      fetchOptions.body = arrayBuffer;
    });
  } else if (options.body &&
             options.processData &&
             typeof options.body !== 'string') {
    fetchOptions.body = JSON.stringify(options.body);
  } else if ('body' in options) {
    fetchOptions.body = options.body;
  } else {
    fetchOptions.body = null;
  }

  Object.keys(options.headers).forEach(function (key) {
    if (options.headers.hasOwnProperty(key)) {
      headers.set(key, options.headers[key]);
    }
  });

  wrappedPromise = wrappedFetch(options.url, fetchOptions);

  if (options.timeout > 0) {
    timer = setTimeout(function () {
      wrappedPromise.reject(new Error('Load timeout for resource: ' +
        options.url));
    }, options.timeout);
  }

  wrappedPromise.promise.then(function (fetchResponse) {
    response = {
      statusCode: fetchResponse.status
    };

    if (options.timeout > 0) {
      clearTimeout(timer);
    }

    if (response.statusCode >= 200 && response.statusCode < 300) {
      return options.binary ? fetchResponse.blob() : fetchResponse.text();
    }

    return fetchResponse.json();
  }).then(function (result) {
    if (response.statusCode >= 200 && response.statusCode < 300) {
      callback(null, response, result);
    } else {
      callback(result, response);
    }
  }).catch(function (error) {
    callback(error, response);
  });

  return {abort: wrappedPromise.reject};
}

function xhRequest(options, callback) {

  var xhr, timer;
  var timedout = false;

  var abortReq = function () {
    xhr.abort();
    cleanUp();
  };

  var timeoutReq = function () {
    timedout = true;
    xhr.abort();
    cleanUp();
  };

  var ret = {abort: abortReq};

  var cleanUp = function () {
    clearTimeout(timer);
    ret.abort = function () {};
    if (xhr) {
      xhr.onprogress = undefined;
      if (xhr.upload) {
        xhr.upload.onprogress = undefined;
      }
      xhr.onreadystatechange = undefined;
      xhr = undefined;
    }
  };

  if (options.xhr) {
    xhr = new options.xhr();
  } else {
    xhr = new XMLHttpRequest();
  }

  try {
    xhr.open(options.method, options.url);
  } catch (exception) {
    return callback(new Error(exception.name || 'Url is invalid'));
  }

  xhr.withCredentials = ('withCredentials' in options) ?
    options.withCredentials : true;

  if (options.method === 'GET') {
    delete options.headers['Content-Type'];
  } else if (options.json) {
    options.headers.Accept = 'application/json';
    options.headers['Content-Type'] = options.headers['Content-Type'] ||
      'application/json';
    if (options.body &&
        options.processData &&
        typeof options.body !== "string") {
      options.body = JSON.stringify(options.body);
    }
  }

  if (options.binary) {
    xhr.responseType = 'arraybuffer';
  }

  if (!('body' in options)) {
    options.body = null;
  }

  for (var key in options.headers) {
    if (options.headers.hasOwnProperty(key)) {
      xhr.setRequestHeader(key, options.headers[key]);
    }
  }

  if (options.timeout > 0) {
    timer = setTimeout(timeoutReq, options.timeout);
    xhr.onprogress = function () {
      clearTimeout(timer);
      if(xhr.readyState !== 4) {
        timer = setTimeout(timeoutReq, options.timeout);
      }
    };
    if (typeof xhr.upload !== 'undefined') { // does not exist in ie9
      xhr.upload.onprogress = xhr.onprogress;
    }
  }

  xhr.onreadystatechange = function () {
    if (xhr.readyState !== 4) {
      return;
    }

    var response = {
      statusCode: xhr.status
    };

    if (xhr.status >= 200 && xhr.status < 300) {
      var data;
      if (options.binary) {
        data = createBlob([xhr.response || ''], {
          type: xhr.getResponseHeader('Content-Type')
        });
      } else {
        data = xhr.responseText;
      }
      callback(null, response, data);
    } else {
      var err = {};
      if (timedout) {
        err = new Error('ETIMEDOUT');
        err.code = 'ETIMEDOUT';
      } else if (typeof xhr.response === 'string') {
        try {
          err = JSON.parse(xhr.response);
        } catch(e) {}
      }
      err.status = xhr.status;
      callback(err);
    }
    cleanUp();
  };

  if (options.body && (options.body instanceof Blob)) {
    readAsArrayBuffer(options.body, function (arrayBuffer) {
      xhr.send(arrayBuffer);
    });
  } else {
    xhr.send(options.body);
  }

  return ret;
}

function testXhr() {
  try {
    new XMLHttpRequest();
    return true;
  } catch (err) {
    return false;
  }
}

var hasXhr = testXhr();

function ajax$1(options, callback) {
  if (hasXhr || options.xhr) {
    return xhRequest(options, callback);
  } else {
    return fetchRequest(options, callback);
  }
}

// the blob already has a type; do nothing
var res$2 = function () {};

function defaultBody() {
  return '';
}

function ajaxCore(options, callback) {

  options = clone(options);

  var defaultOptions = {
    method : "GET",
    headers: {},
    json: true,
    processData: true,
    timeout: 10000,
    cache: false
  };

  options = extend$1(defaultOptions, options);

  function onSuccess(obj, resp, cb) {
    if (!options.binary && options.json && typeof obj === 'string') {
      /* istanbul ignore next */
      try {
        obj = JSON.parse(obj);
      } catch (e) {
        // Probably a malformed JSON from server
        return cb(e);
      }
    }
    if (Array.isArray(obj)) {
      obj = obj.map(function (v) {
        if (v.error || v.missing) {
          return generateErrorFromResponse(v);
        } else {
          return v;
        }
      });
    }
    if (options.binary) {
      res$2(obj, resp);
    }
    cb(null, obj, resp);
  }

  if (options.json) {
    if (!options.binary) {
      options.headers.Accept = 'application/json';
    }
    options.headers['Content-Type'] = options.headers['Content-Type'] ||
      'application/json';
  }

  if (options.binary) {
    options.encoding = null;
    options.json = false;
  }

  if (!options.processData) {
    options.json = false;
  }

  return ajax$1(options, function (err, response, body) {

    if (err) {
      return callback(generateErrorFromResponse(err));
    }

    var error;
    var content_type = response.headers && response.headers['content-type'];
    var data = body || defaultBody();

    // CouchDB doesn't always return the right content-type for JSON data, so
    // we check for ^{ and }$ (ignoring leading/trailing whitespace)
    if (!options.binary && (options.json || !options.processData) &&
        typeof data !== 'object' &&
        (/json/.test(content_type) ||
         (/^[\s]*\{/.test(data) && /\}[\s]*$/.test(data)))) {
      try {
        data = JSON.parse(data.toString());
      } catch (e) {}
    }

    if (response.statusCode >= 200 && response.statusCode < 300) {
      onSuccess(data, response, callback);
    } else {
      error = generateErrorFromResponse(data);
      error.status = response.statusCode;
      callback(error);
    }
  });
}

function ajax(opts, callback) {

  // cache-buster, specifically designed to work around IE's aggressive caching
  // see http://www.dashbay.com/2011/05/internet-explorer-caches-ajax/
  // Also Safari caches POSTs, so we need to cache-bust those too.
  var ua = (navigator && navigator.userAgent) ?
    navigator.userAgent.toLowerCase() : '';

  var isSafari = ua.indexOf('safari') !== -1 && ua.indexOf('chrome') === -1;
  var isIE = ua.indexOf('msie') !== -1;
  var isEdge = ua.indexOf('edge') !== -1;

  // it appears the new version of safari also caches GETs,
  // see https://github.com/pouchdb/pouchdb/issues/5010
  var shouldCacheBust = (isSafari ||
    ((isIE || isEdge) && opts.method === 'GET'));

  var cache = 'cache' in opts ? opts.cache : true;

  var isBlobUrl = /^blob:/.test(opts.url); // don't append nonces for blob URLs

  if (!isBlobUrl && (shouldCacheBust || !cache)) {
    var hasArgs = opts.url.indexOf('?') !== -1;
    opts.url += (hasArgs ? '&' : '?') + '_nonce=' + Date.now();
  }

  return ajaxCore(opts, callback);
}

var CHANGES_BATCH_SIZE = 25;
var MAX_SIMULTANEOUS_REVS = 50;

var supportsBulkGetMap = {};

var log$1 = debug('pouchdb:http');

function readAttachmentsAsBlobOrBuffer(row) {
  var atts = row.doc && row.doc._attachments;
  if (!atts) {
    return;
  }
  Object.keys(atts).forEach(function (filename) {
    var att = atts[filename];
    att.data = b64ToBluffer(att.data, att.content_type);
  });
}

function encodeDocId(id) {
  if (/^_design/.test(id)) {
    return '_design/' + encodeURIComponent(id.slice(8));
  }
  if (/^_local/.test(id)) {
    return '_local/' + encodeURIComponent(id.slice(7));
  }
  return encodeURIComponent(id);
}

function preprocessAttachments$1(doc) {
  if (!doc._attachments || !Object.keys(doc._attachments)) {
    return PouchPromise.resolve();
  }

  return PouchPromise.all(Object.keys(doc._attachments).map(function (key) {
    var attachment = doc._attachments[key];
    if (attachment.data && typeof attachment.data !== 'string') {
      return new PouchPromise(function (resolve) {
        blobToBase64(attachment.data, resolve);
      }).then(function (b64) {
        attachment.data = b64;
      });
    }
  }));
}

function hasUrlPrefix(opts) {
  if (!opts.prefix) {
    return false;
  }

  var protocol = parseUri(opts.prefix).protocol;

  return protocol === 'http' || protocol === 'https';
}

// Get all the information you possibly can about the URI given by name and
// return it as a suitable object.
function getHost(name, opts) {

  // encode db name if opts.prefix is a url (#5574)
  if (hasUrlPrefix(opts)) {
    var dbName = opts.name.substr(opts.prefix.length);
    name = opts.prefix + encodeURIComponent(dbName);
  }

  // Prase the URI into all its little bits
  var uri = parseUri(name);

  // Store the user and password as a separate auth object
  if (uri.user || uri.password) {
    uri.auth = {username: uri.user, password: uri.password};
  }

  // Split the path part of the URI into parts using '/' as the delimiter
  // after removing any leading '/' and any trailing '/'
  var parts = uri.path.replace(/(^\/|\/$)/g, '').split('/');

  // Store the first part as the database name and remove it from the parts
  // array
  uri.db = parts.pop();
  // Prevent double encoding of URI component
  if (uri.db.indexOf('%') === -1) {
    uri.db = encodeURIComponent(uri.db);
  }

  // Restore the path by joining all the remaining parts (all the parts
  // except for the database name) with '/'s
  uri.path = parts.join('/');

  return uri;
}

// Generate a URL with the host data given by opts and the given path
function genDBUrl(opts, path) {
  return genUrl(opts, opts.db + '/' + path);
}

// Generate a URL with the host data given by opts and the given path
function genUrl(opts, path) {
  // If the host already has a path, then we need to have a path delimiter
  // Otherwise, the path delimiter is the empty string
  var pathDel = !opts.path ? '' : '/';

  // If the host already has a path, then we need to have a path delimiter
  // Otherwise, the path delimiter is the empty string
  return opts.protocol + '://' + opts.host +
         (opts.port ? (':' + opts.port) : '') +
         '/' + opts.path + pathDel + path;
}

function paramsToStr(params) {
  return '?' + Object.keys(params).map(function (k) {
    return k + '=' + encodeURIComponent(params[k]);
  }).join('&');
}

// Implements the PouchDB API for dealing with CouchDB instances over HTTP
function HttpPouch(opts, callback) {

  // The functions that will be publicly available for HttpPouch
  var api = this;

  var host = getHost(opts.name, opts);
  var dbUrl = genDBUrl(host, '');

  opts = clone(opts);
  var ajaxOpts = opts.ajax || {};

  if (opts.auth || host.auth) {
    var nAuth = opts.auth || host.auth;
    var str = nAuth.username + ':' + nAuth.password;
    var token = btoa$1(unescape(encodeURIComponent(str)));
    ajaxOpts.headers = ajaxOpts.headers || {};
    ajaxOpts.headers.Authorization = 'Basic ' + token;
  }

  // Not strictly necessary, but we do this because numerous tests
  // rely on swapping ajax in and out.
  api._ajax = ajax;

  function ajax$$(userOpts, options, callback) {
    var reqAjax = userOpts.ajax || {};
    var reqOpts = extend$1(clone(ajaxOpts), reqAjax, options);
    log$1(reqOpts.method + ' ' + reqOpts.url);
    return api._ajax(reqOpts, callback);
  }

  function ajaxPromise(userOpts, opts) {
    return new PouchPromise(function (resolve, reject) {
      ajax$$(userOpts, opts, function (err, res) {
        /* istanbul ignore if */
        if (err) {
          return reject(err);
        }
        resolve(res);
      });
    });
  }

  function adapterFun$$(name, fun) {
    return adapterFun(name, getArguments(function (args) {
      setup().then(function () {
        return fun.apply(this, args);
      }).catch(function (e) {
        var callback = args.pop();
        callback(e);
      });
    }));
  }

  var setupPromise;

  function setup() {
    // TODO: Remove `skipSetup` in favor of `skip_setup` in a future release
    if (opts.skipSetup || opts.skip_setup) {
      return PouchPromise.resolve();
    }

    // If there is a setup in process or previous successful setup
    // done then we will use that
    // If previous setups have been rejected we will try again
    if (setupPromise) {
      return setupPromise;
    }

    var checkExists = {method: 'GET', url: dbUrl};
    setupPromise = ajaxPromise({}, checkExists).catch(function (err) {
      if (err && err.status && err.status === 404) {
        // Doesnt exist, create it
        explainError(404, 'PouchDB is just detecting if the remote exists.');
        return ajaxPromise({}, {method: 'PUT', url: dbUrl});
      } else {
        return PouchPromise.reject(err);
      }
    }).catch(function (err) {
      // If we try to create a database that already exists, skipped in
      // istanbul since its catching a race condition.
      /* istanbul ignore if */
      if (err && err.status && err.status === 412) {
        return true;
      }
      return PouchPromise.reject(err);
    });

    setupPromise.catch(function () {
      setupPromise = null;
    });

    return setupPromise;
  }

  setTimeout(function () {
    callback(null, api);
  });

  api.type = function () {
    return 'http';
  };

  api.id = adapterFun$$('id', function (callback) {
    ajax$$({}, {method: 'GET', url: genUrl(host, '')}, function (err, result) {
      var uuid = (result && result.uuid) ?
        (result.uuid + host.db) : genDBUrl(host, '');
      callback(null, uuid);
    });
  });

  api.request = adapterFun$$('request', function (options, callback) {
    options.url = genDBUrl(host, options.url);
    ajax$$({}, options, callback);
  });

  // Sends a POST request to the host calling the couchdb _compact function
  //    version: The version of CouchDB it is running
  api.compact = adapterFun$$('compact', function (opts, callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    opts = clone(opts);
    ajax$$(opts, {
      url: genDBUrl(host, '_compact'),
      method: 'POST'
    }, function () {
      function ping() {
        api.info(function (err, res) {
          if (res && !res.compact_running) {
            callback(null, {ok: true});
          } else {
            setTimeout(ping, opts.interval || 200);
          }
        });
      }
      // Ping the http if it's finished compaction
      ping();
    });
  });

  api.bulkGet = adapterFun('bulkGet', function (opts, callback) {
    var self = this;

    function doBulkGet(cb) {
      var params = {};
      if (opts.revs) {
        params.revs = true;
      }
      if (opts.attachments) {
        /* istanbul ignore next */
        params.attachments = true;
      }
      ajax$$({}, {
        url: genDBUrl(host, '_bulk_get' + paramsToStr(params)),
        method: 'POST',
        body: { docs: opts.docs}
      }, cb);
    }

    function doBulkGetShim() {
      // avoid "url too long error" by splitting up into multiple requests
      var batchSize = MAX_SIMULTANEOUS_REVS;
      var numBatches = Math.ceil(opts.docs.length / batchSize);
      var numDone = 0;
      var results = new Array(numBatches);

      function onResult(batchNum) {
        return function (err, res) {
          // err is impossible because shim returns a list of errs in that case
          results[batchNum] = res.results;
          if (++numDone === numBatches) {
            callback(null, {results: flatten(results)});
          }
        };
      }

      for (var i = 0; i < numBatches; i++) {
        var subOpts = pick(opts, ['revs', 'attachments']);
        subOpts.ajax = ajaxOpts;
        subOpts.docs = opts.docs.slice(i * batchSize,
          Math.min(opts.docs.length, (i + 1) * batchSize));
        bulkGet(self, subOpts, onResult(i));
      }
    }

    // mark the whole database as either supporting or not supporting _bulk_get
    var dbUrl = genUrl(host, '');
    var supportsBulkGet = supportsBulkGetMap[dbUrl];

    if (typeof supportsBulkGet !== 'boolean') {
      // check if this database supports _bulk_get
      doBulkGet(function (err, res) {
        /* istanbul ignore else */
        if (err) {
          var status = Math.floor(err.status / 100);
          /* istanbul ignore else */
          if (status === 4 || status === 5) { // 40x or 50x
            supportsBulkGetMap[dbUrl] = false;
            explainError(
              err.status,
              'PouchDB is just detecting if the remote ' +
              'supports the _bulk_get API.'
            );
            doBulkGetShim();
          } else {
            callback(err);
          }
        } else {
          supportsBulkGetMap[dbUrl] = true;
          callback(null, res);
        }
      });
    } else if (supportsBulkGet) {
      /* istanbul ignore next */
      doBulkGet(callback);
    } else {
      doBulkGetShim();
    }
  });

  // Calls GET on the host, which gets back a JSON string containing
  //    couchdb: A welcome string
  //    version: The version of CouchDB it is running
  api._info = function (callback) {
    setup().then(function () {
      ajax$$({}, {
        method: 'GET',
        url: genDBUrl(host, '')
      }, function (err, res) {
        /* istanbul ignore next */
        if (err) {
        return callback(err);
        }
        res.host = genDBUrl(host, '');
        callback(null, res);
      });
    }).catch(callback);
  };

  // Get the document with the given id from the database given by host.
  // The id could be solely the _id in the database, or it may be a
  // _design/ID or _local/ID path
  api.get = adapterFun$$('get', function (id, opts, callback) {
    // If no options were given, set the callback to the second parameter
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    opts = clone(opts);

    // List of parameters to add to the GET request
    var params = {};

    if (opts.revs) {
      params.revs = true;
    }

    if (opts.revs_info) {
      params.revs_info = true;
    }

    if (opts.open_revs) {
      if (opts.open_revs !== "all") {
        opts.open_revs = JSON.stringify(opts.open_revs);
      }
      params.open_revs = opts.open_revs;
    }

    if (opts.rev) {
      params.rev = opts.rev;
    }

    if (opts.conflicts) {
      params.conflicts = opts.conflicts;
    }

    id = encodeDocId(id);

    // Set the options for the ajax call
    var options = {
      method: 'GET',
      url: genDBUrl(host, id + paramsToStr(params))
    };

    function fetchAttachments(doc) {
      var atts = doc._attachments;
      var filenames = atts && Object.keys(atts);
      if (!atts || !filenames.length) {
        return;
      }
      // we fetch these manually in separate XHRs, because
      // Sync Gateway would normally send it back as multipart/mixed,
      // which we cannot parse. Also, this is more efficient than
      // receiving attachments as base64-encoded strings.
      function fetch() {

        if (!filenames.length) {
          return null;
        }

        var filename = filenames.pop();
        var att = atts[filename];
        var path = encodeDocId(doc._id) + '/' + encodeAttachmentId(filename) +
          '?rev=' + doc._rev;
        return ajaxPromise(opts, {
          method: 'GET',
          url: genDBUrl(host, path),
          binary: true
        }).then(function (blob) {
          if (opts.binary) {
            return blob;
          }
          return new PouchPromise(function (resolve) {
            blobToBase64(blob, resolve);
          });
        }).then(function (data) {
          delete att.stub;
          delete att.length;
          att.data = data;
        });
      }

      // This limits the number of parallel xhr requests to 5 any time
      // to avoid issues with maximum browser request limits
      return new PromisePool(fetch, 5, {promise: PouchPromise}).start();
    }

    function fetchAllAttachments(docOrDocs) {
      if (Array.isArray(docOrDocs)) {
        return PouchPromise.all(docOrDocs.map(function (doc) {
          if (doc.ok) {
            return fetchAttachments(doc.ok);
          }
        }));
      }
      return fetchAttachments(docOrDocs);
    }

    ajaxPromise(opts, options).then(function (res) {
      return PouchPromise.resolve().then(function () {
        if (opts.attachments) {
          return fetchAllAttachments(res);
        }
      }).then(function () {
        callback(null, res);
      });
    }).catch(callback);
  });

  // Delete the document given by doc from the database given by host.
  api.remove = adapterFun$$('remove',
      function (docOrId, optsOrRev, opts, callback) {
    var doc;
    if (typeof optsOrRev === 'string') {
      // id, rev, opts, callback style
      doc = {
        _id: docOrId,
        _rev: optsOrRev
      };
      if (typeof opts === 'function') {
        callback = opts;
        opts = {};
      }
    } else {
      // doc, opts, callback style
      doc = docOrId;
      if (typeof optsOrRev === 'function') {
        callback = optsOrRev;
        opts = {};
      } else {
        callback = opts;
        opts = optsOrRev;
      }
    }

    var rev = (doc._rev || opts.rev);

    // Delete the document
    ajax$$(opts, {
      method: 'DELETE',
      url: genDBUrl(host, encodeDocId(doc._id)) + '?rev=' + rev
    }, callback);
  });

  function encodeAttachmentId(attachmentId) {
    return attachmentId.split("/").map(encodeURIComponent).join("/");
  }

  // Get the attachment
  api.getAttachment =
    adapterFun$$('getAttachment', function (docId, attachmentId, opts,
                                                callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    var params = opts.rev ? ('?rev=' + opts.rev) : '';
    var url = genDBUrl(host, encodeDocId(docId)) + '/' +
      encodeAttachmentId(attachmentId) + params;
    ajax$$(opts, {
      method: 'GET',
      url: url,
      binary: true
    }, callback);
  });

  // Remove the attachment given by the id and rev
  api.removeAttachment =
    adapterFun$$('removeAttachment', function (docId, attachmentId, rev,
                                                   callback) {

    var url = genDBUrl(host, encodeDocId(docId) + '/' +
      encodeAttachmentId(attachmentId)) + '?rev=' + rev;

    ajax$$({}, {
      method: 'DELETE',
      url: url
    }, callback);
  });

  // Add the attachment given by blob and its contentType property
  // to the document with the given id, the revision given by rev, and
  // add it to the database given by host.
  api.putAttachment =
    adapterFun$$('putAttachment', function (docId, attachmentId, rev, blob,
                                                type, callback) {
    if (typeof type === 'function') {
      callback = type;
      type = blob;
      blob = rev;
      rev = null;
    }
    var id = encodeDocId(docId) + '/' + encodeAttachmentId(attachmentId);
    var url = genDBUrl(host, id);
    if (rev) {
      url += '?rev=' + rev;
    }

    if (typeof blob === 'string') {
      // input is assumed to be a base64 string
      var binary;
      try {
        binary = atob$1(blob);
      } catch (err) {
        return callback(createError(BAD_ARG,
                        'Attachment is not a valid base64 string'));
      }
      blob = binary ? binStringToBluffer(binary, type) : '';
    }

    var opts = {
      headers: {'Content-Type': type},
      method: 'PUT',
      url: url,
      processData: false,
      body: blob,
      timeout: ajaxOpts.timeout || 60000
    };
    // Add the attachment
    ajax$$({}, opts, callback);
  });

  // Update/create multiple documents given by req in the database
  // given by host.
  api._bulkDocs = function (req, opts, callback) {
    // If new_edits=false then it prevents the database from creating
    // new revision numbers for the documents. Instead it just uses
    // the old ones. This is used in database replication.
    req.new_edits = opts.new_edits;

    setup().then(function () {
      return PouchPromise.all(req.docs.map(preprocessAttachments$1));
    }).then(function () {
      // Update/create the documents
      ajax$$(opts, {
        method: 'POST',
        url: genDBUrl(host, '_bulk_docs'),
        timeout: opts.timeout,
        body: req
      }, function (err, results) {
        if (err) {
          return callback(err);
        }
        results.forEach(function (result) {
          result.ok = true; // smooths out cloudant not adding this
        });
        callback(null, results);
      });
    }).catch(callback);
  };


  // Update/create document
  api._put = function (doc, opts, callback) {
    setup().then(function () {
      return preprocessAttachments$1(doc);
    }).then(function () {
      // Update/create the document
      ajax$$(opts, {
        method: 'PUT',
        url: genDBUrl(host, encodeDocId(doc._id)),
        body: doc
      }, function (err, result) {
        if (err) {
          return callback(err);
        }
        callback(null, result);
      });
    }).catch(callback);
  };


  // Get a listing of the documents in the database given
  // by host and ordered by increasing id.
  api.allDocs = adapterFun$$('allDocs', function (opts, callback) {
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    opts = clone(opts);

    // List of parameters to add to the GET request
    var params = {};
    var body;
    var method = 'GET';

    if (opts.conflicts) {
      params.conflicts = true;
    }

    if (opts.descending) {
      params.descending = true;
    }

    if (opts.include_docs) {
      params.include_docs = true;
    }

    // added in CouchDB 1.6.0
    if (opts.attachments) {
      params.attachments = true;
    }

    if (opts.key) {
      params.key = JSON.stringify(opts.key);
    }

    if (opts.start_key) {
      opts.startkey = opts.start_key;
    }

    if (opts.startkey) {
      params.startkey = JSON.stringify(opts.startkey);
    }

    if (opts.end_key) {
      opts.endkey = opts.end_key;
    }

    if (opts.endkey) {
      params.endkey = JSON.stringify(opts.endkey);
    }

    if (typeof opts.inclusive_end !== 'undefined') {
      params.inclusive_end = !!opts.inclusive_end;
    }

    if (typeof opts.limit !== 'undefined') {
      params.limit = opts.limit;
    }

    if (typeof opts.skip !== 'undefined') {
      params.skip = opts.skip;
    }

    var paramStr = paramsToStr(params);

    if (typeof opts.keys !== 'undefined') {
      method = 'POST';
      body = {keys: opts.keys};
    }

    // Get the document listing
    ajaxPromise(opts, {
      method: method,
      url: genDBUrl(host, '_all_docs' + paramStr),
      body: body
    }).then(function (res) {
      if (opts.include_docs && opts.attachments && opts.binary) {
        res.rows.forEach(readAttachmentsAsBlobOrBuffer);
      }
      callback(null, res);
    }).catch(callback);
  });

  // Get a list of changes made to documents in the database given by host.
  // TODO According to the README, there should be two other methods here,
  // api.changes.addListener and api.changes.removeListener.
  api._changes = function (opts) {

    // We internally page the results of a changes request, this means
    // if there is a large set of changes to be returned we can start
    // processing them quicker instead of waiting on the entire
    // set of changes to return and attempting to process them at once
    var batchSize = 'batch_size' in opts ? opts.batch_size : CHANGES_BATCH_SIZE;

    opts = clone(opts);
    opts.timeout = ('timeout' in opts) ? opts.timeout :
      ('timeout' in ajaxOpts) ? ajaxOpts.timeout :
      30 * 1000;

    // We give a 5 second buffer for CouchDB changes to respond with
    // an ok timeout (if a timeout it set)
    var params = opts.timeout ? {timeout: opts.timeout - (5 * 1000)} : {};
    var limit = (typeof opts.limit !== 'undefined') ? opts.limit : false;
    var returnDocs;
    if ('return_docs' in opts) {
      returnDocs = opts.return_docs;
    } else if ('returnDocs' in opts) {
      // TODO: Remove 'returnDocs' in favor of 'return_docs' in a future release
      returnDocs = opts.returnDocs;
    } else {
      returnDocs = true;
    }
    //
    var leftToFetch = limit;

    if (opts.style) {
      params.style = opts.style;
    }

    if (opts.include_docs || opts.filter && typeof opts.filter === 'function') {
      params.include_docs = true;
    }

    if (opts.attachments) {
      params.attachments = true;
    }

    if (opts.continuous) {
      params.feed = 'longpoll';
    }

    if (opts.conflicts) {
      params.conflicts = true;
    }

    if (opts.descending) {
      params.descending = true;
    }

    if ('heartbeat' in opts) {
      // If the heartbeat value is false, it disables the default heartbeat
      if (opts.heartbeat) {
        params.heartbeat = opts.heartbeat;
      }
    } else {
      // Default heartbeat to 10 seconds
      params.heartbeat = 10000;
    }

    if (opts.filter && typeof opts.filter === 'string') {
      params.filter = opts.filter;
    }

    if (opts.view && typeof opts.view === 'string') {
      params.filter = '_view';
      params.view = opts.view;
    }

    // If opts.query_params exists, pass it through to the changes request.
    // These parameters may be used by the filter on the source database.
    if (opts.query_params && typeof opts.query_params === 'object') {
      for (var param_name in opts.query_params) {
        /* istanbul ignore else */
        if (opts.query_params.hasOwnProperty(param_name)) {
          params[param_name] = opts.query_params[param_name];
        }
      }
    }

    var method = 'GET';
    var body;

    if (opts.doc_ids) {
      // set this automagically for the user; it's annoying that couchdb
      // requires both a "filter" and a "doc_ids" param.
      params.filter = '_doc_ids';
      method = 'POST';
      body = {doc_ids: opts.doc_ids };
    }

    var xhr;
    var lastFetchedSeq;

    // Get all the changes starting wtih the one immediately after the
    // sequence number given by since.
    var fetch = function (since, callback) {
      if (opts.aborted) {
        return;
      }
      params.since = since;
      // "since" can be any kind of json object in Coudant/CouchDB 2.x
      /* istanbul ignore next */
      if (typeof params.since === "object") {
        params.since = JSON.stringify(params.since);
      }

      if (opts.descending) {
        if (limit) {
          params.limit = leftToFetch;
        }
      } else {
        params.limit = (!limit || leftToFetch > batchSize) ?
          batchSize : leftToFetch;
      }

      // Set the options for the ajax call
      var xhrOpts = {
        method: method,
        url: genDBUrl(host, '_changes' + paramsToStr(params)),
        timeout: opts.timeout,
        body: body
      };
      lastFetchedSeq = since;

      /* istanbul ignore if */
      if (opts.aborted) {
        return;
      }

      // Get the changes
      setup().then(function () {
        xhr = ajax$$(opts, xhrOpts, callback);
      }).catch(callback);
    };

    // If opts.since exists, get all the changes from the sequence
    // number given by opts.since. Otherwise, get all the changes
    // from the sequence number 0.
    var results = {results: []};

    var fetched = function (err, res) {
      if (opts.aborted) {
        return;
      }
      var raw_results_length = 0;
      // If the result of the ajax call (res) contains changes (res.results)
      if (res && res.results) {
        raw_results_length = res.results.length;
        results.last_seq = res.last_seq;
        // For each change
        var req = {};
        req.query = opts.query_params;
        res.results = res.results.filter(function (c) {
          leftToFetch--;
          var ret = filterChange(opts)(c);
          if (ret) {
            if (opts.include_docs && opts.attachments && opts.binary) {
              readAttachmentsAsBlobOrBuffer(c);
            }
            if (returnDocs) {
              results.results.push(c);
            }
            opts.onChange(c);
          }
          return ret;
        });
      } else if (err) {
        // In case of an error, stop listening for changes and call
        // opts.complete
        opts.aborted = true;
        opts.complete(err);
        return;
      }

      // The changes feed may have timed out with no results
      // if so reuse last update sequence
      if (res && res.last_seq) {
        lastFetchedSeq = res.last_seq;
      }

      var finished = (limit && leftToFetch <= 0) ||
        (res && raw_results_length < batchSize) ||
        (opts.descending);

      if ((opts.continuous && !(limit && leftToFetch <= 0)) || !finished) {
        // Queue a call to fetch again with the newest sequence number
        setTimeout(function () { fetch(lastFetchedSeq, fetched); }, 0);
      } else {
        // We're done, call the callback
        opts.complete(null, results);
      }
    };

    fetch(opts.since || 0, fetched);

    // Return a method to cancel this method from processing any more
    return {
      cancel: function () {
        opts.aborted = true;
        if (xhr) {
          xhr.abort();
        }
      }
    };
  };

  // Given a set of document/revision IDs (given by req), tets the subset of
  // those that do NOT correspond to revisions stored in the database.
  // See http://wiki.apache.org/couchdb/HttpPostRevsDiff
  api.revsDiff = adapterFun$$('revsDiff', function (req, opts, callback) {
    // If no options were given, set the callback to be the second parameter
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }

    // Get the missing document/revision IDs
    ajax$$(opts, {
      method: 'POST',
      url: genDBUrl(host, '_revs_diff'),
      body: req
    }, callback);
  });

  api._close = function (callback) {
    callback();
  };

  api._destroy = function (options, callback) {
    ajax$$(options, {
      url: genDBUrl(host, ''),
      method: 'DELETE'
    }, function (err, resp) {
      if (err && err.status && err.status !== 404) {
        return callback(err);
      }
      callback(null, resp);
    });
  };
}

// HttpPouch is a valid adapter.
HttpPouch.valid = function () {
  return true;
};

function HttpPouch$1 (PouchDB) {
  PouchDB.adapter('http', HttpPouch, false);
  PouchDB.adapter('https', HttpPouch, false);
}

function pad(str, padWith, upToLength) {
  var padding = '';
  var targetLength = upToLength - str.length;
  /* istanbul ignore next */
  while (padding.length < targetLength) {
    padding += padWith;
  }
  return padding;
}

function padLeft(str, padWith, upToLength) {
  var padding = pad(str, padWith, upToLength);
  return padding + str;
}

var MIN_MAGNITUDE = -324; // verified by -Number.MIN_VALUE
var MAGNITUDE_DIGITS = 3; // ditto
var SEP = ''; // set to '_' for easier debugging 

function collate(a, b) {

  if (a === b) {
    return 0;
  }

  a = normalizeKey(a);
  b = normalizeKey(b);

  var ai = collationIndex(a);
  var bi = collationIndex(b);
  if ((ai - bi) !== 0) {
    return ai - bi;
  }
  if (a === null) {
    return 0;
  }
  switch (typeof a) {
    case 'number':
      return a - b;
    case 'boolean':
      return a === b ? 0 : (a < b ? -1 : 1);
    case 'string':
      return stringCollate(a, b);
  }
  return Array.isArray(a) ? arrayCollate(a, b) : objectCollate(a, b);
}

// couch considers null/NaN/Infinity/-Infinity === undefined,
// for the purposes of mapreduce indexes. also, dates get stringified.
function normalizeKey(key) {
  switch (typeof key) {
    case 'undefined':
      return null;
    case 'number':
      if (key === Infinity || key === -Infinity || isNaN(key)) {
        return null;
      }
      return key;
    case 'object':
      var origKey = key;
      if (Array.isArray(key)) {
        var len = key.length;
        key = new Array(len);
        for (var i = 0; i < len; i++) {
          key[i] = normalizeKey(origKey[i]);
        }
      /* istanbul ignore next */
      } else if (key instanceof Date) {
        return key.toJSON();
      } else if (key !== null) { // generic object
        key = {};
        for (var k in origKey) {
          if (origKey.hasOwnProperty(k)) {
            var val = origKey[k];
            if (typeof val !== 'undefined') {
              key[k] = normalizeKey(val);
            }
          }
        }
      }
  }
  return key;
}

function indexify(key) {
  if (key !== null) {
    switch (typeof key) {
      case 'boolean':
        return key ? 1 : 0;
      case 'number':
        return numToIndexableString(key);
      case 'string':
        // We've to be sure that key does not contain \u0000
        // Do order-preserving replacements:
        // 0 -> 1, 1
        // 1 -> 1, 2
        // 2 -> 2, 2
        return key
          .replace(/\u0002/g, '\u0002\u0002')
          .replace(/\u0001/g, '\u0001\u0002')
          .replace(/\u0000/g, '\u0001\u0001');
      case 'object':
        var isArray = Array.isArray(key);
        var arr = isArray ? key : Object.keys(key);
        var i = -1;
        var len = arr.length;
        var result = '';
        if (isArray) {
          while (++i < len) {
            result += toIndexableString(arr[i]);
          }
        } else {
          while (++i < len) {
            var objKey = arr[i];
            result += toIndexableString(objKey) +
                toIndexableString(key[objKey]);
          }
        }
        return result;
    }
  }
  return '';
}

// convert the given key to a string that would be appropriate
// for lexical sorting, e.g. within a database, where the
// sorting is the same given by the collate() function.
function toIndexableString(key) {
  var zero = '\u0000';
  key = normalizeKey(key);
  return collationIndex(key) + SEP + indexify(key) + zero;
}

function parseNumber(str, i) {
  var originalIdx = i;
  var num;
  var zero = str[i] === '1';
  if (zero) {
    num = 0;
    i++;
  } else {
    var neg = str[i] === '0';
    i++;
    var numAsString = '';
    var magAsString = str.substring(i, i + MAGNITUDE_DIGITS);
    var magnitude = parseInt(magAsString, 10) + MIN_MAGNITUDE;
    /* istanbul ignore next */
    if (neg) {
      magnitude = -magnitude;
    }
    i += MAGNITUDE_DIGITS;
    while (true) {
      var ch = str[i];
      if (ch === '\u0000') {
        break;
      } else {
        numAsString += ch;
      }
      i++;
    }
    numAsString = numAsString.split('.');
    if (numAsString.length === 1) {
      num = parseInt(numAsString, 10);
    } else {
      /* istanbul ignore next */
      num = parseFloat(numAsString[0] + '.' + numAsString[1]);
    }
    /* istanbul ignore next */
    if (neg) {
      num = num - 10;
    }
    /* istanbul ignore next */
    if (magnitude !== 0) {
      // parseFloat is more reliable than pow due to rounding errors
      // e.g. Number.MAX_VALUE would return Infinity if we did
      // num * Math.pow(10, magnitude);
      num = parseFloat(num + 'e' + magnitude);
    }
  }
  return {num: num, length : i - originalIdx};
}

// move up the stack while parsing
// this function moved outside of parseIndexableString for performance
function pop(stack, metaStack) {
  var obj = stack.pop();

  if (metaStack.length) {
    var lastMetaElement = metaStack[metaStack.length - 1];
    if (obj === lastMetaElement.element) {
      // popping a meta-element, e.g. an object whose value is another object
      metaStack.pop();
      lastMetaElement = metaStack[metaStack.length - 1];
    }
    var element = lastMetaElement.element;
    var lastElementIndex = lastMetaElement.index;
    if (Array.isArray(element)) {
      element.push(obj);
    } else if (lastElementIndex === stack.length - 2) { // obj with key+value
      var key = stack.pop();
      element[key] = obj;
    } else {
      stack.push(obj); // obj with key only
    }
  }
}

function parseIndexableString(str) {
  var stack = [];
  var metaStack = []; // stack for arrays and objects
  var i = 0;

  /*eslint no-constant-condition: ["error", { "checkLoops": false }]*/
  while (true) {
    var collationIndex = str[i++];
    if (collationIndex === '\u0000') {
      if (stack.length === 1) {
        return stack.pop();
      } else {
        pop(stack, metaStack);
        continue;
      }
    }
    switch (collationIndex) {
      case '1':
        stack.push(null);
        break;
      case '2':
        stack.push(str[i] === '1');
        i++;
        break;
      case '3':
        var parsedNum = parseNumber(str, i);
        stack.push(parsedNum.num);
        i += parsedNum.length;
        break;
      case '4':
        var parsedStr = '';
        /*eslint no-constant-condition: ["error", { "checkLoops": false }]*/
        while (true) {
          var ch = str[i];
          if (ch === '\u0000') {
            break;
          }
          parsedStr += ch;
          i++;
        }
        // perform the reverse of the order-preserving replacement
        // algorithm (see above)
        parsedStr = parsedStr.replace(/\u0001\u0001/g, '\u0000')
          .replace(/\u0001\u0002/g, '\u0001')
          .replace(/\u0002\u0002/g, '\u0002');
        stack.push(parsedStr);
        break;
      case '5':
        var arrayElement = { element: [], index: stack.length };
        stack.push(arrayElement.element);
        metaStack.push(arrayElement);
        break;
      case '6':
        var objElement = { element: {}, index: stack.length };
        stack.push(objElement.element);
        metaStack.push(objElement);
        break;
      /* istanbul ignore next */
      default:
        throw new Error(
          'bad collationIndex or unexpectedly reached end of input: ' +
            collationIndex);
    }
  }
}

function arrayCollate(a, b) {
  var len = Math.min(a.length, b.length);
  for (var i = 0; i < len; i++) {
    var sort = collate(a[i], b[i]);
    if (sort !== 0) {
      return sort;
    }
  }
  return (a.length === b.length) ? 0 :
    (a.length > b.length) ? 1 : -1;
}
function stringCollate(a, b) {
  // See: https://github.com/daleharvey/pouchdb/issues/40
  // This is incompatible with the CouchDB implementation, but its the
  // best we can do for now
  return (a === b) ? 0 : ((a > b) ? 1 : -1);
}
function objectCollate(a, b) {
  var ak = Object.keys(a), bk = Object.keys(b);
  var len = Math.min(ak.length, bk.length);
  for (var i = 0; i < len; i++) {
    // First sort the keys
    var sort = collate(ak[i], bk[i]);
    if (sort !== 0) {
      return sort;
    }
    // if the keys are equal sort the values
    sort = collate(a[ak[i]], b[bk[i]]);
    if (sort !== 0) {
      return sort;
    }

  }
  return (ak.length === bk.length) ? 0 :
    (ak.length > bk.length) ? 1 : -1;
}
// The collation is defined by erlangs ordered terms
// the atoms null, true, false come first, then numbers, strings,
// arrays, then objects
// null/undefined/NaN/Infinity/-Infinity are all considered null
function collationIndex(x) {
  var id = ['boolean', 'number', 'string', 'object'];
  var idx = id.indexOf(typeof x);
  //false if -1 otherwise true, but fast!!!!1
  if (~idx) {
    if (x === null) {
      return 1;
    }
    if (Array.isArray(x)) {
      return 5;
    }
    return idx < 3 ? (idx + 2) : (idx + 3);
  }
  /* istanbul ignore next */
  if (Array.isArray(x)) {
    return 5;
  }
}

// conversion:
// x yyy zz...zz
// x = 0 for negative, 1 for 0, 2 for positive
// y = exponent (for negative numbers negated) moved so that it's >= 0
// z = mantisse
function numToIndexableString(num) {

  if (num === 0) {
    return '1';
  }

  // convert number to exponential format for easier and
  // more succinct string sorting
  var expFormat = num.toExponential().split(/e\+?/);
  var magnitude = parseInt(expFormat[1], 10);

  var neg = num < 0;

  var result = neg ? '0' : '2';

  // first sort by magnitude
  // it's easier if all magnitudes are positive
  var magForComparison = ((neg ? -magnitude : magnitude) - MIN_MAGNITUDE);
  var magString = padLeft((magForComparison).toString(), '0', MAGNITUDE_DIGITS);

  result += SEP + magString;

  // then sort by the factor
  var factor = Math.abs(parseFloat(expFormat[0])); // [1..10)
  /* istanbul ignore next */
  if (neg) { // for negative reverse ordering
    factor = 10 - factor;
  }

  var factorStr = factor.toFixed(20);

  // strip zeros from the end
  factorStr = factorStr.replace(/\.?0+$/, '');

  result += SEP + factorStr;

  return result;
}

/*
 * Simple task queue to sequentialize actions. Assumes
 * callbacks will eventually fire (once).
 */

function TaskQueue$1() {
  this.promise = new PouchPromise(function (fulfill) {fulfill(); });
}
TaskQueue$1.prototype.add = function (promiseFactory) {
  this.promise = this.promise.catch(function () {
    // just recover
  }).then(function () {
    return promiseFactory();
  });
  return this.promise;
};
TaskQueue$1.prototype.finish = function () {
  return this.promise;
};

function createView(opts) {
  var sourceDB = opts.db;
  var viewName = opts.viewName;
  var mapFun = opts.map;
  var reduceFun = opts.reduce;
  var temporary = opts.temporary;

  // the "undefined" part is for backwards compatibility
  var viewSignature = mapFun.toString() + (reduceFun && reduceFun.toString()) +
    'undefined';

  var cachedViews;
  if (!temporary) {
    // cache this to ensure we don't try to update the same view twice
    cachedViews = sourceDB._cachedViews = sourceDB._cachedViews || {};
    if (cachedViews[viewSignature]) {
      return cachedViews[viewSignature];
    }
  }

  var promiseForView = sourceDB.info().then(function (info) {

    var depDbName = info.db_name + '-mrview-' +
      (temporary ? 'temp' : stringMd5(viewSignature));

    // save the view name in the source db so it can be cleaned up if necessary
    // (e.g. when the _design doc is deleted, remove all associated view data)
    function diffFunction(doc) {
      doc.views = doc.views || {};
      var fullViewName = viewName;
      if (fullViewName.indexOf('/') === -1) {
        fullViewName = viewName + '/' + viewName;
      }
      var depDbs = doc.views[fullViewName] = doc.views[fullViewName] || {};
      /* istanbul ignore if */
      if (depDbs[depDbName]) {
        return; // no update necessary
      }
      depDbs[depDbName] = true;
      return doc;
    }
    return upsert(sourceDB, '_local/mrviews', diffFunction).then(function () {
      return sourceDB.registerDependentDatabase(depDbName).then(function (res) {
        var db = res.db;
        db.auto_compaction = true;
        var view = {
          name: depDbName,
          db: db,
          sourceDB: sourceDB,
          adapter: sourceDB.adapter,
          mapFun: mapFun,
          reduceFun: reduceFun
        };
        return view.db.get('_local/lastSeq').catch(function (err) {
          /* istanbul ignore if */
          if (err.status !== 404) {
            throw err;
          }
        }).then(function (lastSeqDoc) {
          view.seq = lastSeqDoc ? lastSeqDoc.seq : 0;
          if (cachedViews) {
            view.db.once('destroyed', function () {
              delete cachedViews[viewSignature];
            });
          }
          return view;
        });
      });
    });
  });

  if (cachedViews) {
    cachedViews[viewSignature] = promiseForView;
  }
  return promiseForView;
}

function QueryParseError(message) {
  this.status = 400;
  this.name = 'query_parse_error';
  this.message = message;
  this.error = true;
  try {
    Error.captureStackTrace(this, QueryParseError);
  } catch (e) {}
}

inherits(QueryParseError, Error);

function NotFoundError(message) {
  this.status = 404;
  this.name = 'not_found';
  this.message = message;
  this.error = true;
  try {
    Error.captureStackTrace(this, NotFoundError);
  } catch (e) {}
}

inherits(NotFoundError, Error);

function BuiltInError(message) {
  this.status = 500;
  this.name = 'invalid_value';
  this.message = message;
  this.error = true;
  try {
    Error.captureStackTrace(this, BuiltInError);
  } catch (e) {}
}

inherits(BuiltInError, Error);

function createBuiltInError(name) {
  var message = 'builtin ' + name +
    ' function requires map values to be numbers' +
    ' or number arrays';
  return new BuiltInError(message);
}

function sum(values) {
  var result = 0;
  for (var i = 0, len = values.length; i < len; i++) {
    var num = values[i];
    if (typeof num !== 'number') {
      if (Array.isArray(num)) {
        // lists of numbers are also allowed, sum them separately
        result = typeof result === 'number' ? [result] : result;
        for (var j = 0, jLen = num.length; j < jLen; j++) {
          var jNum = num[j];
          if (typeof jNum !== 'number') {
            throw createBuiltInError('_sum');
          } else if (typeof result[j] === 'undefined') {
            result.push(jNum);
          } else {
            result[j] += jNum;
          }
        }
      } else { // not array/number
        throw createBuiltInError('_sum');
      }
    } else if (typeof result === 'number') {
      result += num;
    } else { // add number to array
      result[0] += num;
    }
  }
  return result;
}

var log$2 = guardedConsole.bind(null, 'log');
var isArray = Array.isArray;
var toJSON = JSON.parse;

function evalFunctionWithEval(func, emit) {
  return scopedEval(
    "return (" + func.replace(/;\s*$/, "") + ");",
    {
      emit: emit,
      sum: sum,
      log: log$2,
      isArray: isArray,
      toJSON: toJSON
    }
  );
}

var promisedCallback = function (promise, callback) {
  if (callback) {
    promise.then(function (res) {
      process.nextTick(function () {
        callback(null, res);
      });
    }, function (reason) {
      process.nextTick(function () {
        callback(reason);
      });
    });
  }
  return promise;
};

var callbackify = function (fun) {
  return getArguments(function (args) {
    var cb = args.pop();
    var promise = fun.apply(this, args);
    if (typeof cb === 'function') {
      promisedCallback(promise, cb);
    }
    return promise;
  });
};

// Promise finally util similar to Q.finally
var fin = function (promise, finalPromiseFactory) {
  return promise.then(function (res) {
    return finalPromiseFactory().then(function () {
      return res;
    });
  }, function (reason) {
    return finalPromiseFactory().then(function () {
      throw reason;
    });
  });
};

var sequentialize = function (queue, promiseFactory) {
  return function () {
    var args = arguments;
    var that = this;
    return queue.add(function () {
      return promiseFactory.apply(that, args);
    });
  };
};

// uniq an array of strings, order not guaranteed
// similar to underscore/lodash _.uniq
var uniq = function (arr) {
  var map = {};

  for (var i = 0, len = arr.length; i < len; i++) {
    map['$' + arr[i]] = true;
  }

  var keys = Object.keys(map);
  var output = new Array(keys.length);

  for (i = 0, len = keys.length; i < len; i++) {
    output[i] = keys[i].substring(1);
  }
  return output;
};

var persistentQueues = {};
var tempViewQueue = new TaskQueue$1();
var CHANGES_BATCH_SIZE$1 = 50;

function parseViewName(name) {
  // can be either 'ddocname/viewname' or just 'viewname'
  // (where the ddoc name is the same)
  return name.indexOf('/') === -1 ? [name, name] : name.split('/');
}

function isGenOne(changes) {
  // only return true if the current change is 1-
  // and there are no other leafs
  return changes.length === 1 && /^1-/.test(changes[0].rev);
}

function emitError(db, e) {
  try {
    db.emit('error', e);
  } catch (err) {
    guardedConsole('error',
      'The user\'s map/reduce function threw an uncaught error.\n' +
      'You can debug this error by doing:\n' +
      'myDatabase.on(\'error\', function (err) { debugger; });\n' +
      'Please double-check your map/reduce function.');
    guardedConsole('error', e);
  }
}

function tryCode$1(db, fun, args) {
  // emit an event if there was an error thrown by a map/reduce function.
  // putting try/catches in a single function also avoids deoptimizations.
  try {
    return {
      output : fun.apply(null, args)
    };
  } catch (e) {
    emitError(db, e);
    return {error: e};
  }
}

function sortByKeyThenValue(x, y) {
  var keyCompare = collate(x.key, y.key);
  return keyCompare !== 0 ? keyCompare : collate(x.value, y.value);
}

function sliceResults(results, limit, skip) {
  skip = skip || 0;
  if (typeof limit === 'number') {
    return results.slice(skip, limit + skip);
  } else if (skip > 0) {
    return results.slice(skip);
  }
  return results;
}

function rowToDocId(row) {
  var val = row.value;
  // Users can explicitly specify a joined doc _id, or it
  // defaults to the doc _id that emitted the key/value.
  var docId = (val && typeof val === 'object' && val._id) || row.id;
  return docId;
}

function readAttachmentsAsBlobOrBuffer$1(res) {
  res.rows.forEach(function (row) {
    var atts = row.doc && row.doc._attachments;
    if (!atts) {
      return;
    }
    Object.keys(atts).forEach(function (filename) {
      var att = atts[filename];
      atts[filename].data = b64ToBluffer(att.data, att.content_type);
    });
  });
}

function postprocessAttachments(opts) {
  return function (res) {
    if (opts.include_docs && opts.attachments && opts.binary) {
      readAttachmentsAsBlobOrBuffer$1(res);
    }
    return res;
  };
}

var builtInReduce = {
  _sum: function (keys, values) {
    return sum(values);
  },

  _count: function (keys, values) {
    return values.length;
  },

  _stats: function (keys, values) {
    // no need to implement rereduce=true, because Pouch
    // will never call it
    function sumsqr(values) {
      var _sumsqr = 0;
      for (var i = 0, len = values.length; i < len; i++) {
        var num = values[i];
        _sumsqr += (num * num);
      }
      return _sumsqr;
    }
    return {
      sum     : sum(values),
      min     : Math.min.apply(null, values),
      max     : Math.max.apply(null, values),
      count   : values.length,
      sumsqr : sumsqr(values)
    };
  }
};

function addHttpParam(paramName, opts, params, asJson) {
  // add an http param from opts to params, optionally json-encoded
  var val = opts[paramName];
  if (typeof val !== 'undefined') {
    if (asJson) {
      val = encodeURIComponent(JSON.stringify(val));
    }
    params.push(paramName + '=' + val);
  }
}

function coerceInteger(integerCandidate) {
  if (typeof integerCandidate !== 'undefined') {
    var asNumber = Number(integerCandidate);
    // prevents e.g. '1foo' or '1.1' being coerced to 1
    if (!isNaN(asNumber) && asNumber === parseInt(integerCandidate, 10)) {
      return asNumber;
    } else {
      return integerCandidate;
    }
  }
}

function coerceOptions(opts) {
  opts.group_level = coerceInteger(opts.group_level);
  opts.limit = coerceInteger(opts.limit);
  opts.skip = coerceInteger(opts.skip);
  return opts;
}

function checkPositiveInteger(number) {
  if (number) {
    if (typeof number !== 'number') {
      return  new QueryParseError('Invalid value for integer: "' +
      number + '"');
    }
    if (number < 0) {
      return new QueryParseError('Invalid value for positive integer: ' +
        '"' + number + '"');
    }
  }
}

function checkQueryParseError(options, fun) {
  var startkeyName = options.descending ? 'endkey' : 'startkey';
  var endkeyName = options.descending ? 'startkey' : 'endkey';

  if (typeof options[startkeyName] !== 'undefined' &&
    typeof options[endkeyName] !== 'undefined' &&
    collate(options[startkeyName], options[endkeyName]) > 0) {
    throw new QueryParseError('No rows can match your key range, ' +
    'reverse your start_key and end_key or set {descending : true}');
  } else if (fun.reduce && options.reduce !== false) {
    if (options.include_docs) {
      throw new QueryParseError('{include_docs:true} is invalid for reduce');
    } else if (options.keys && options.keys.length > 1 &&
        !options.group && !options.group_level) {
      throw new QueryParseError('Multi-key fetches for reduce views must use ' +
      '{group: true}');
    }
  }
  ['group_level', 'limit', 'skip'].forEach(function (optionName) {
    var error = checkPositiveInteger(options[optionName]);
    if (error) {
      throw error;
    }
  });
}

function httpQuery(db, fun, opts) {
  // List of parameters to add to the PUT request
  var params = [];
  var body;
  var method = 'GET';

  // If opts.reduce exists and is defined, then add it to the list
  // of parameters.
  // If reduce=false then the results are that of only the map function
  // not the final result of map and reduce.
  addHttpParam('reduce', opts, params);
  addHttpParam('include_docs', opts, params);
  addHttpParam('attachments', opts, params);
  addHttpParam('limit', opts, params);
  addHttpParam('descending', opts, params);
  addHttpParam('group', opts, params);
  addHttpParam('group_level', opts, params);
  addHttpParam('skip', opts, params);
  addHttpParam('stale', opts, params);
  addHttpParam('conflicts', opts, params);
  addHttpParam('startkey', opts, params, true);
  addHttpParam('start_key', opts, params, true);
  addHttpParam('endkey', opts, params, true);
  addHttpParam('end_key', opts, params, true);
  addHttpParam('inclusive_end', opts, params);
  addHttpParam('key', opts, params, true);

  // Format the list of parameters into a valid URI query string
  params = params.join('&');
  params = params === '' ? '' : '?' + params;

  // If keys are supplied, issue a POST to circumvent GET query string limits
  // see http://wiki.apache.org/couchdb/HTTP_view_API#Querying_Options
  if (typeof opts.keys !== 'undefined') {
    var MAX_URL_LENGTH = 2000;
    // according to http://stackoverflow.com/a/417184/680742,
    // the de facto URL length limit is 2000 characters

    var keysAsString =
      'keys=' + encodeURIComponent(JSON.stringify(opts.keys));
    if (keysAsString.length + params.length + 1 <= MAX_URL_LENGTH) {
      // If the keys are short enough, do a GET. we do this to work around
      // Safari not understanding 304s on POSTs (see pouchdb/pouchdb#1239)
      params += (params[0] === '?' ? '&' : '?') + keysAsString;
    } else {
      method = 'POST';
      if (typeof fun === 'string') {
        body = {keys: opts.keys};
      } else { // fun is {map : mapfun}, so append to this
        fun.keys = opts.keys;
      }
    }
  }

  // We are referencing a query defined in the design doc
  if (typeof fun === 'string') {
    var parts = parseViewName(fun);
    return db.request({
      method: method,
      url: '_design/' + parts[0] + '/_view/' + parts[1] + params,
      body: body
    }).then(postprocessAttachments(opts));
  }

  // We are using a temporary view, terrible for performance, good for testing
  body = body || {};
  Object.keys(fun).forEach(function (key) {
    if (Array.isArray(fun[key])) {
      body[key] = fun[key];
    } else {
      body[key] = fun[key].toString();
    }
  });
  return db.request({
    method: 'POST',
    url: '_temp_view' + params,
    body: body
  }).then(postprocessAttachments(opts));
}

// custom adapters can define their own api._query
// and override the default behavior
/* istanbul ignore next */
function customQuery(db, fun, opts) {
  return new PouchPromise(function (resolve, reject) {
    db._query(fun, opts, function (err, res) {
      if (err) {
        return reject(err);
      }
      resolve(res);
    });
  });
}

// custom adapters can define their own api._viewCleanup
// and override the default behavior
/* istanbul ignore next */
function customViewCleanup(db) {
  return new PouchPromise(function (resolve, reject) {
    db._viewCleanup(function (err, res) {
      if (err) {
        return reject(err);
      }
      resolve(res);
    });
  });
}

function defaultsTo(value) {
  return function (reason) {
    /* istanbul ignore else */
    if (reason.status === 404) {
      return value;
    } else {
      throw reason;
    }
  };
}

// returns a promise for a list of docs to update, based on the input docId.
// the order doesn't matter, because post-3.2.0, bulkDocs
// is an atomic operation in all three adapters.
function getDocsToPersist(docId, view, docIdsToChangesAndEmits) {
  var metaDocId = '_local/doc_' + docId;
  var defaultMetaDoc = {_id: metaDocId, keys: []};
  var docData = docIdsToChangesAndEmits[docId];
  var indexableKeysToKeyValues = docData.indexableKeysToKeyValues;
  var changes = docData.changes;

  function getMetaDoc() {
    if (isGenOne(changes)) {
      // generation 1, so we can safely assume initial state
      // for performance reasons (avoids unnecessary GETs)
      return PouchPromise.resolve(defaultMetaDoc);
    }
    return view.db.get(metaDocId).catch(defaultsTo(defaultMetaDoc));
  }

  function getKeyValueDocs(metaDoc) {
    if (!metaDoc.keys.length) {
      // no keys, no need for a lookup
      return PouchPromise.resolve({rows: []});
    }
    return view.db.allDocs({
      keys: metaDoc.keys,
      include_docs: true
    });
  }

  function processKvDocs(metaDoc, kvDocsRes) {
    var kvDocs = [];
    var oldKeysMap = {};

    for (var i = 0, len = kvDocsRes.rows.length; i < len; i++) {
      var row = kvDocsRes.rows[i];
      var doc = row.doc;
      if (!doc) { // deleted
        continue;
      }
      kvDocs.push(doc);
      oldKeysMap[doc._id] = true;
      doc._deleted = !indexableKeysToKeyValues[doc._id];
      if (!doc._deleted) {
        var keyValue = indexableKeysToKeyValues[doc._id];
        if ('value' in keyValue) {
          doc.value = keyValue.value;
        }
      }
    }

    var newKeys = Object.keys(indexableKeysToKeyValues);
    newKeys.forEach(function (key) {
      if (!oldKeysMap[key]) {
        // new doc
        var kvDoc = {
          _id: key
        };
        var keyValue = indexableKeysToKeyValues[key];
        if ('value' in keyValue) {
          kvDoc.value = keyValue.value;
        }
        kvDocs.push(kvDoc);
      }
    });
    metaDoc.keys = uniq(newKeys.concat(metaDoc.keys));
    kvDocs.push(metaDoc);

    return kvDocs;
  }

  return getMetaDoc().then(function (metaDoc) {
    return getKeyValueDocs(metaDoc).then(function (kvDocsRes) {
      return processKvDocs(metaDoc, kvDocsRes);
    });
  });
}

// updates all emitted key/value docs and metaDocs in the mrview database
// for the given batch of documents from the source database
function saveKeyValues(view, docIdsToChangesAndEmits, seq) {
  var seqDocId = '_local/lastSeq';
  return view.db.get(seqDocId)
  .catch(defaultsTo({_id: seqDocId, seq: 0}))
  .then(function (lastSeqDoc) {
    var docIds = Object.keys(docIdsToChangesAndEmits);
    return PouchPromise.all(docIds.map(function (docId) {
      return getDocsToPersist(docId, view, docIdsToChangesAndEmits);
    })).then(function (listOfDocsToPersist) {
      var docsToPersist = flatten(listOfDocsToPersist);
      lastSeqDoc.seq = seq;
      docsToPersist.push(lastSeqDoc);
      // write all docs in a single operation, update the seq once
      return view.db.bulkDocs({docs : docsToPersist});
    });
  });
}

function getQueue(view) {
  var viewName = typeof view === 'string' ? view : view.name;
  var queue = persistentQueues[viewName];
  if (!queue) {
    queue = persistentQueues[viewName] = new TaskQueue$1();
  }
  return queue;
}

function updateView(view) {
  return sequentialize(getQueue(view), function () {
    return updateViewInQueue(view);
  })();
}

function updateViewInQueue(view) {
  // bind the emit function once
  var mapResults;
  var doc;

  function emit(key, value) {
    var output = {id: doc._id, key: normalizeKey(key)};
    // Don't explicitly store the value unless it's defined and non-null.
    // This saves on storage space, because often people don't use it.
    if (typeof value !== 'undefined' && value !== null) {
      output.value = normalizeKey(value);
    }
    mapResults.push(output);
  }

  var mapFun;
  // for temp_views one can use emit(doc, emit), see #38
  if (typeof view.mapFun === "function" && view.mapFun.length === 2) {
    var origMap = view.mapFun;
    mapFun = function (doc) {
      return origMap(doc, emit);
    };
  } else {
    mapFun = evalFunctionWithEval(view.mapFun.toString(), emit);
  }

  var currentSeq = view.seq || 0;

  function processChange(docIdsToChangesAndEmits, seq) {
    return function () {
      return saveKeyValues(view, docIdsToChangesAndEmits, seq);
    };
  }

  var queue = new TaskQueue$1();
  // TODO(neojski): https://github.com/daleharvey/pouchdb/issues/1521

  return new PouchPromise(function (resolve, reject) {

    function complete() {
      queue.finish().then(function () {
        view.seq = currentSeq;
        resolve();
      });
    }

    function processNextBatch() {
      view.sourceDB.changes({
        conflicts: true,
        include_docs: true,
        style: 'all_docs',
        since: currentSeq,
        limit: CHANGES_BATCH_SIZE$1
      }).on('complete', function (response) {
        var results = response.results;
        if (!results.length) {
          return complete();
        }
        var docIdsToChangesAndEmits = {};
        for (var i = 0, l = results.length; i < l; i++) {
          var change = results[i];
          if (change.doc._id[0] !== '_') {
            mapResults = [];
            doc = change.doc;

            if (!doc._deleted) {
              tryCode$1(view.sourceDB, mapFun, [doc]);
            }
            mapResults.sort(sortByKeyThenValue);

            var indexableKeysToKeyValues = {};
            var lastKey;
            for (var j = 0, jl = mapResults.length; j < jl; j++) {
              var obj = mapResults[j];
              var complexKey = [obj.key, obj.id];
              if (collate(obj.key, lastKey) === 0) {
                complexKey.push(j); // dup key+id, so make it unique
              }
              var indexableKey = toIndexableString(complexKey);
              indexableKeysToKeyValues[indexableKey] = obj;
              lastKey = obj.key;
            }
            docIdsToChangesAndEmits[change.doc._id] = {
              indexableKeysToKeyValues: indexableKeysToKeyValues,
              changes: change.changes
            };
          }
          currentSeq = change.seq;
        }
        queue.add(processChange(docIdsToChangesAndEmits, currentSeq));
        if (results.length < CHANGES_BATCH_SIZE$1) {
          return complete();
        }
        return processNextBatch();
      }).on('error', onError);
      /* istanbul ignore next */
      function onError(err) {
        reject(err);
      }
    }

    processNextBatch();
  });
}

function reduceView(view, results, options) {
  if (options.group_level === 0) {
    delete options.group_level;
  }

  var shouldGroup = options.group || options.group_level;

  var reduceFun;
  if (builtInReduce[view.reduceFun]) {
    reduceFun = builtInReduce[view.reduceFun];
  } else {
    reduceFun = evalFunctionWithEval(view.reduceFun.toString());
  }

  var groups = [];
  var lvl = isNaN(options.group_level) ? Number.POSITIVE_INFINITY :
    options.group_level;
  results.forEach(function (e) {
    var last = groups[groups.length - 1];
    var groupKey = shouldGroup ? e.key : null;

    // only set group_level for array keys
    if (shouldGroup && Array.isArray(groupKey)) {
      groupKey = groupKey.slice(0, lvl);
    }

    if (last && collate(last.groupKey, groupKey) === 0) {
      last.keys.push([e.key, e.id]);
      last.values.push(e.value);
      return;
    }
    groups.push({
      keys: [[e.key, e.id]],
      values: [e.value],
      groupKey: groupKey
    });
  });
  results = [];
  for (var i = 0, len = groups.length; i < len; i++) {
    var e = groups[i];
    var reduceTry = tryCode$1(view.sourceDB, reduceFun,
      [e.keys, e.values, false]);
    if (reduceTry.error && reduceTry.error instanceof BuiltInError) {
      // CouchDB returns an error if a built-in errors out
      throw reduceTry.error;
    }
    results.push({
      // CouchDB just sets the value to null if a non-built-in errors out
      value: reduceTry.error ? null : reduceTry.output,
      key: e.groupKey
    });
  }
  // no total_rows/offset when reducing
  return {rows: sliceResults(results, options.limit, options.skip)};
}

function queryView(view, opts) {
  return sequentialize(getQueue(view), function () {
    return queryViewInQueue(view, opts);
  })();
}

function queryViewInQueue(view, opts) {
  var totalRows;
  var shouldReduce = view.reduceFun && opts.reduce !== false;
  var skip = opts.skip || 0;
  if (typeof opts.keys !== 'undefined' && !opts.keys.length) {
    // equivalent query
    opts.limit = 0;
    delete opts.keys;
  }

  function fetchFromView(viewOpts) {
    viewOpts.include_docs = true;
    return view.db.allDocs(viewOpts).then(function (res) {
      totalRows = res.total_rows;
      return res.rows.map(function (result) {

        // implicit migration - in older versions of PouchDB,
        // we explicitly stored the doc as {id: ..., key: ..., value: ...}
        // this is tested in a migration test
        /* istanbul ignore next */
        if ('value' in result.doc && typeof result.doc.value === 'object' &&
            result.doc.value !== null) {
          var keys = Object.keys(result.doc.value).sort();
          // this detection method is not perfect, but it's unlikely the user
          // emitted a value which was an object with these 3 exact keys
          var expectedKeys = ['id', 'key', 'value'];
          if (!(keys < expectedKeys || keys > expectedKeys)) {
            return result.doc.value;
          }
        }

        var parsedKeyAndDocId = parseIndexableString(result.doc._id);
        return {
          key: parsedKeyAndDocId[0],
          id: parsedKeyAndDocId[1],
          value: ('value' in result.doc ? result.doc.value : null)
        };
      });
    });
  }

  function onMapResultsReady(rows) {
    var finalResults;
    if (shouldReduce) {
      finalResults = reduceView(view, rows, opts);
    } else {
      finalResults = {
        total_rows: totalRows,
        offset: skip,
        rows: rows
      };
    }
    if (opts.include_docs) {
      var docIds = uniq(rows.map(rowToDocId));

      return view.sourceDB.allDocs({
        keys: docIds,
        include_docs: true,
        conflicts: opts.conflicts,
        attachments: opts.attachments,
        binary: opts.binary
      }).then(function (allDocsRes) {
        var docIdsToDocs = {};
        allDocsRes.rows.forEach(function (row) {
          if (row.doc) {
            docIdsToDocs['$' + row.id] = row.doc;
          }
        });
        rows.forEach(function (row) {
          var docId = rowToDocId(row);
          var doc = docIdsToDocs['$' + docId];
          if (doc) {
            row.doc = doc;
          }
        });
        return finalResults;
      });
    } else {
      return finalResults;
    }
  }

  if (typeof opts.keys !== 'undefined') {
    var keys = opts.keys;
    var fetchPromises = keys.map(function (key) {
      var viewOpts = {
        startkey : toIndexableString([key]),
        endkey   : toIndexableString([key, {}])
      };
      return fetchFromView(viewOpts);
    });
    return PouchPromise.all(fetchPromises).then(flatten).then(onMapResultsReady);
  } else { // normal query, no 'keys'
    var viewOpts = {
      descending : opts.descending
    };
    if (opts.start_key) {
        opts.startkey = opts.start_key;
    }
    if (opts.end_key) {
        opts.endkey = opts.end_key;
    }
    if (typeof opts.startkey !== 'undefined') {
      viewOpts.startkey = opts.descending ?
        toIndexableString([opts.startkey, {}]) :
        toIndexableString([opts.startkey]);
    }
    if (typeof opts.endkey !== 'undefined') {
      var inclusiveEnd = opts.inclusive_end !== false;
      if (opts.descending) {
        inclusiveEnd = !inclusiveEnd;
      }

      viewOpts.endkey = toIndexableString(
        inclusiveEnd ? [opts.endkey, {}] : [opts.endkey]);
    }
    if (typeof opts.key !== 'undefined') {
      var keyStart = toIndexableString([opts.key]);
      var keyEnd = toIndexableString([opts.key, {}]);
      if (viewOpts.descending) {
        viewOpts.endkey = keyStart;
        viewOpts.startkey = keyEnd;
      } else {
        viewOpts.startkey = keyStart;
        viewOpts.endkey = keyEnd;
      }
    }
    if (!shouldReduce) {
      if (typeof opts.limit === 'number') {
        viewOpts.limit = opts.limit;
      }
      viewOpts.skip = skip;
    }
    return fetchFromView(viewOpts).then(onMapResultsReady);
  }
}

function httpViewCleanup(db) {
  return db.request({
    method: 'POST',
    url: '_view_cleanup'
  });
}

function localViewCleanup(db) {
  return db.get('_local/mrviews').then(function (metaDoc) {
    var docsToViews = {};
    Object.keys(metaDoc.views).forEach(function (fullViewName) {
      var parts = parseViewName(fullViewName);
      var designDocName = '_design/' + parts[0];
      var viewName = parts[1];
      docsToViews[designDocName] = docsToViews[designDocName] || {};
      docsToViews[designDocName][viewName] = true;
    });
    var opts = {
      keys : Object.keys(docsToViews),
      include_docs : true
    };
    return db.allDocs(opts).then(function (res) {
      var viewsToStatus = {};
      res.rows.forEach(function (row) {
        var ddocName = row.key.substring(8);
        Object.keys(docsToViews[row.key]).forEach(function (viewName) {
          var fullViewName = ddocName + '/' + viewName;
          /* istanbul ignore if */
          if (!metaDoc.views[fullViewName]) {
            // new format, without slashes, to support PouchDB 2.2.0
            // migration test in pouchdb's browser.migration.js verifies this
            fullViewName = viewName;
          }
          var viewDBNames = Object.keys(metaDoc.views[fullViewName]);
          // design doc deleted, or view function nonexistent
          var statusIsGood = row.doc && row.doc.views &&
            row.doc.views[viewName];
          viewDBNames.forEach(function (viewDBName) {
            viewsToStatus[viewDBName] =
              viewsToStatus[viewDBName] || statusIsGood;
          });
        });
      });
      var dbsToDelete = Object.keys(viewsToStatus).filter(
        function (viewDBName) { return !viewsToStatus[viewDBName]; });
      var destroyPromises = dbsToDelete.map(function (viewDBName) {
        return sequentialize(getQueue(viewDBName), function () {
          return new db.constructor(viewDBName, db.__opts).destroy();
        })();
      });
      return PouchPromise.all(destroyPromises).then(function () {
        return {ok: true};
      });
    });
  }, defaultsTo({ok: true}));
}

var viewCleanup = callbackify(function () {
  var db = this;
  if (db.type() === 'http') {
    return httpViewCleanup(db);
  }
  /* istanbul ignore next */
  if (typeof db._viewCleanup === 'function') {
    return customViewCleanup(db);
  }
  return localViewCleanup(db);
});

function queryPromised(db, fun, opts) {
  if (db.type() === 'http') {
    return httpQuery(db, fun, opts);
  }

  /* istanbul ignore next */
  if (typeof db._query === 'function') {
    return customQuery(db, fun, opts);
  }

  if (typeof fun !== 'string') {
    // temp_view
    checkQueryParseError(opts, fun);

    var createViewOpts = {
      db : db,
      viewName : 'temp_view/temp_view',
      map : fun.map,
      reduce : fun.reduce,
      temporary : true
    };
    tempViewQueue.add(function () {
      return createView(createViewOpts).then(function (view) {
        function cleanup() {
          return view.db.destroy();
        }
        return fin(updateView(view).then(function () {
          return queryView(view, opts);
        }), cleanup);
      });
    });
    return tempViewQueue.finish();
  } else {
    // persistent view
    var fullViewName = fun;
    var parts = parseViewName(fullViewName);
    var designDocName = parts[0];
    var viewName = parts[1];
    return db.get('_design/' + designDocName).then(function (doc) {
      var fun = doc.views && doc.views[viewName];

      if (!fun || typeof fun.map !== 'string') {
        throw new NotFoundError('ddoc ' + designDocName +
        ' has no view named ' + viewName);
      }
      checkQueryParseError(opts, fun);

      var createViewOpts = {
        db : db,
        viewName : fullViewName,
        map : fun.map,
        reduce : fun.reduce
      };
      return createView(createViewOpts).then(function (view) {
        if (opts.stale === 'ok' || opts.stale === 'update_after') {
          if (opts.stale === 'update_after') {
            process.nextTick(function () {
              updateView(view);
            });
          }
          return queryView(view, opts);
        } else { // stale not ok
          return updateView(view).then(function () {
            return queryView(view, opts);
          });
        }
      });
    });
  }
}

var query = function (fun, opts, callback) {
  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }
  opts = opts ? coerceOptions(opts) : {};

  if (typeof fun === 'function') {
    fun = {map : fun};
  }

  var db = this;
  var promise = PouchPromise.resolve().then(function () {
    return queryPromised(db, fun, opts);
  });
  promisedCallback(promise, callback);
  return promise;
};


var mapreduce = {
  query: query,
  viewCleanup: viewCleanup
};

function isGenOne$1(rev) {
  return /^1-/.test(rev);
}

function fileHasChanged(localDoc, remoteDoc, filename) {
  return !localDoc._attachments ||
         !localDoc._attachments[filename] ||
         localDoc._attachments[filename].digest !== remoteDoc._attachments[filename].digest;
}

function getDocAttachments(db, doc) {
  var filenames = Object.keys(doc._attachments);
  return PouchPromise.all(filenames.map(function (filename) {
    return db.getAttachment(doc._id, filename, {rev: doc._rev});
  }));
}

function getDocAttachmentsFromTargetOrSource(target, src, doc) {
  var doCheckForLocalAttachments = src.type() === 'http' && target.type() !== 'http';
  var filenames = Object.keys(doc._attachments);

  if (!doCheckForLocalAttachments) {
    return getDocAttachments(src, doc);
  }

  return target.get(doc._id).then(function (localDoc) {
    return PouchPromise.all(filenames.map(function (filename) {
      if (fileHasChanged(localDoc, doc, filename)) {
        return src.getAttachment(doc._id, filename);
      }

      return target.getAttachment(localDoc._id, filename);
    }));
  }).catch(function (error) {
    /* istanbul ignore if */
    if (error.status !== 404) {
      throw error;
    }

    return getDocAttachments(src, doc);
  });
}

function createBulkGetOpts(diffs) {
  var requests = [];
  Object.keys(diffs).forEach(function (id) {
    var missingRevs = diffs[id].missing;
    missingRevs.forEach(function (missingRev) {
      requests.push({
        id: id,
        rev: missingRev
      });
    });
  });

  return {
    docs: requests,
    revs: true
  };
}

//
// Fetch all the documents from the src as described in the "diffs",
// which is a mapping of docs IDs to revisions. If the state ever
// changes to "cancelled", then the returned promise will be rejected.
// Else it will be resolved with a list of fetched documents.
//
function getDocs(src, target, diffs, state) {
  diffs = clone(diffs); // we do not need to modify this

  var resultDocs = [],
      ok = true;

  function getAllDocs() {

    var bulkGetOpts = createBulkGetOpts(diffs);

    if (!bulkGetOpts.docs.length) { // optimization: skip empty requests
      return;
    }

    return src.bulkGet(bulkGetOpts).then(function (bulkGetResponse) {
      /* istanbul ignore if */
      if (state.cancelled) {
        throw new Error('cancelled');
      }
      return PouchPromise.all(bulkGetResponse.results.map(function (bulkGetInfo) {
        return PouchPromise.all(bulkGetInfo.docs.map(function (doc) {
          var remoteDoc = doc.ok;

          if (doc.error) {
            // when AUTO_COMPACTION is set, docs can be returned which look
            // like this: {"missing":"1-7c3ac256b693c462af8442f992b83696"}
            ok = false;
          }

          if (!remoteDoc || !remoteDoc._attachments) {
            return remoteDoc;
          }

          return getDocAttachmentsFromTargetOrSource(target, src, remoteDoc).then(function (attachments) {
            var filenames = Object.keys(remoteDoc._attachments);
            attachments.forEach(function (attachment, i) {
              var att = remoteDoc._attachments[filenames[i]];
              delete att.stub;
              delete att.length;
              att.data = attachment;
            });

            return remoteDoc;
          });
        }));
      }))

      .then(function (results) {
        resultDocs = resultDocs.concat(flatten(results).filter(Boolean));
      });
    });
  }

  function hasAttachments(doc) {
    return doc._attachments && Object.keys(doc._attachments).length > 0;
  }

  function hasConflicts(doc) {
    return doc._conflicts && doc._conflicts.length > 0;
  }

  function fetchRevisionOneDocs(ids) {
    // Optimization: fetch gen-1 docs and attachments in
    // a single request using _all_docs
    return src.allDocs({
      keys: ids,
      include_docs: true,
      conflicts: true
    }).then(function (res) {
      if (state.cancelled) {
        throw new Error('cancelled');
      }
      res.rows.forEach(function (row) {
        if (row.deleted || !row.doc || !isGenOne$1(row.value.rev) ||
            hasAttachments(row.doc) || hasConflicts(row.doc)) {
          // if any of these conditions apply, we need to fetch using get()
          return;
        }

        // the doc we got back from allDocs() is sufficient
        resultDocs.push(row.doc);
        delete diffs[row.id];
      });
    });
  }

  function getRevisionOneDocs() {
    // filter out the generation 1 docs and get them
    // leaving the non-generation one docs to be got otherwise
    var ids = Object.keys(diffs).filter(function (id) {
      var missing = diffs[id].missing;
      return missing.length === 1 && isGenOne$1(missing[0]);
    });
    if (ids.length > 0) {
      return fetchRevisionOneDocs(ids);
    }
  }

  function returnResult() {
    return { ok:ok, docs:resultDocs };
  }

  return PouchPromise.resolve()
    .then(getRevisionOneDocs)
    .then(getAllDocs)
    .then(returnResult);
}

var CHECKPOINT_VERSION = 1;
var REPLICATOR = "pouchdb";
// This is an arbitrary number to limit the
// amount of replication history we save in the checkpoint.
// If we save too much, the checkpoing docs will become very big,
// if we save fewer, we'll run a greater risk of having to
// read all the changes from 0 when checkpoint PUTs fail
// CouchDB 2.0 has a more involved history pruning,
// but let's go for the simple version for now.
var CHECKPOINT_HISTORY_SIZE = 5;
var LOWEST_SEQ = 0;

function updateCheckpoint(db, id, checkpoint, session, returnValue) {
  return db.get(id).catch(function (err) {
    if (err.status === 404) {
      if (db.type() === 'http') {
        explainError(
          404, 'PouchDB is just checking if a remote checkpoint exists.'
        );
      }
      return {
        session_id: session,
        _id: id,
        history: [],
        replicator: REPLICATOR,
        version: CHECKPOINT_VERSION
      };
    }
    throw err;
  }).then(function (doc) {
    if (returnValue.cancelled) {
      return;
    }

    // if the checkpoint has not changed, do not update
    if (doc.last_seq === checkpoint) {
      return;
    }

    // Filter out current entry for this replication
    doc.history = (doc.history || []).filter(function (item) {
      return item.session_id !== session;
    });

    // Add the latest checkpoint to history
    doc.history.unshift({
      last_seq: checkpoint,
      session_id: session
    });

    // Just take the last pieces in history, to
    // avoid really big checkpoint docs.
    // see comment on history size above
    doc.history = doc.history.slice(0, CHECKPOINT_HISTORY_SIZE);

    doc.version = CHECKPOINT_VERSION;
    doc.replicator = REPLICATOR;

    doc.session_id = session;
    doc.last_seq = checkpoint;

    return db.put(doc).catch(function (err) {
      if (err.status === 409) {
        // retry; someone is trying to write a checkpoint simultaneously
        return updateCheckpoint(db, id, checkpoint, session, returnValue);
      }
      throw err;
    });
  });
}

function Checkpointer(src, target, id, returnValue) {
  this.src = src;
  this.target = target;
  this.id = id;
  this.returnValue = returnValue;
}

Checkpointer.prototype.writeCheckpoint = function (checkpoint, session) {
  var self = this;
  return this.updateTarget(checkpoint, session).then(function () {
    return self.updateSource(checkpoint, session);
  });
};

Checkpointer.prototype.updateTarget = function (checkpoint, session) {
  return updateCheckpoint(this.target, this.id, checkpoint,
    session, this.returnValue);
};

Checkpointer.prototype.updateSource = function (checkpoint, session) {
  var self = this;
  if (this.readOnlySource) {
    return PouchPromise.resolve(true);
  }
  return updateCheckpoint(this.src, this.id, checkpoint,
    session, this.returnValue)
    .catch(function (err) {
      if (isForbiddenError(err)) {
        self.readOnlySource = true;
        return true;
      }
      throw err;
    });
};

var comparisons = {
  "undefined": function (targetDoc, sourceDoc) {
    // This is the previous comparison function
    if (collate(targetDoc.last_seq, sourceDoc.last_seq) === 0) {
      return sourceDoc.last_seq;
    }
    /* istanbul ignore next */
    return 0;
  },
  "1": function (targetDoc, sourceDoc) {
    // This is the comparison function ported from CouchDB
    return compareReplicationLogs(sourceDoc, targetDoc).last_seq;
  }
};

Checkpointer.prototype.getCheckpoint = function () {
  var self = this;
  return self.target.get(self.id).then(function (targetDoc) {
    if (self.readOnlySource) {
      return PouchPromise.resolve(targetDoc.last_seq);
    }

    return self.src.get(self.id).then(function (sourceDoc) {
      // Since we can't migrate an old version doc to a new one
      // (no session id), we just go with the lowest seq in this case
      /* istanbul ignore if */
      if (targetDoc.version !== sourceDoc.version) {
        return LOWEST_SEQ;
      }

      var version;
      if (targetDoc.version) {
        version = targetDoc.version.toString();
      } else {
        version = "undefined";
      }

      if (version in comparisons) {
        return comparisons[version](targetDoc, sourceDoc);
      }
      /* istanbul ignore next */
      return LOWEST_SEQ;
    }, function (err) {
      if (err.status === 404 && targetDoc.last_seq) {
        return self.src.put({
          _id: self.id,
          last_seq: LOWEST_SEQ
        }).then(function () {
          return LOWEST_SEQ;
        }, function (err) {
          if (isForbiddenError(err)) {
            self.readOnlySource = true;
            return targetDoc.last_seq;
          }
          /* istanbul ignore next */
          return LOWEST_SEQ;
        });
      }
      throw err;
    });
  }).catch(function (err) {
    if (err.status !== 404) {
      throw err;
    }
    return LOWEST_SEQ;
  });
};
// This checkpoint comparison is ported from CouchDBs source
// they come from here:
// https://github.com/apache/couchdb-couch-replicator/blob/master/src/couch_replicator.erl#L863-L906

function compareReplicationLogs(srcDoc, tgtDoc) {
  if (srcDoc.session_id === tgtDoc.session_id) {
    return {
      last_seq: srcDoc.last_seq,
      history: srcDoc.history
    };
  }

  return compareReplicationHistory(srcDoc.history, tgtDoc.history);
}

function compareReplicationHistory(sourceHistory, targetHistory) {
  // the erlang loop via function arguments is not so easy to repeat in JS
  // therefore, doing this as recursion
  var S = sourceHistory[0];
  var sourceRest = sourceHistory.slice(1);
  var T = targetHistory[0];
  var targetRest = targetHistory.slice(1);

  if (!S || targetHistory.length === 0) {
    return {
      last_seq: LOWEST_SEQ,
      history: []
    };
  }

  var sourceId = S.session_id;
  /* istanbul ignore if */
  if (hasSessionId(sourceId, targetHistory)) {
    return {
      last_seq: S.last_seq,
      history: sourceHistory
    };
  }

  var targetId = T.session_id;
  if (hasSessionId(targetId, sourceRest)) {
    return {
      last_seq: T.last_seq,
      history: targetRest
    };
  }

  return compareReplicationHistory(sourceRest, targetRest);
}

function hasSessionId(sessionId, history) {
  var props = history[0];
  var rest = history.slice(1);

  if (!sessionId || history.length === 0) {
    return false;
  }

  if (sessionId === props.session_id) {
    return true;
  }

  return hasSessionId(sessionId, rest);
}

function isForbiddenError(err) {
  return typeof err.status === 'number' && Math.floor(err.status / 100) === 4;
}

var STARTING_BACK_OFF = 0;

function backOff(opts, returnValue, error, callback) {
  if (opts.retry === false) {
    returnValue.emit('error', error);
    returnValue.removeAllListeners();
    return;
  }
  if (typeof opts.back_off_function !== 'function') {
    opts.back_off_function = defaultBackOff;
  }
  returnValue.emit('requestError', error);
  if (returnValue.state === 'active' || returnValue.state === 'pending') {
    returnValue.emit('paused', error);
    returnValue.state = 'stopped';
    var backOffSet = function backoffTimeSet() {
      opts.current_back_off = STARTING_BACK_OFF;
    };
    var removeBackOffSetter = function removeBackOffTimeSet() {
      returnValue.removeListener('active', backOffSet);
    };
    returnValue.once('paused', removeBackOffSetter);
    returnValue.once('active', backOffSet);
  }

  opts.current_back_off = opts.current_back_off || STARTING_BACK_OFF;
  opts.current_back_off = opts.back_off_function(opts.current_back_off);
  setTimeout(callback, opts.current_back_off);
}

function sortObjectPropertiesByKey(queryParams) {
  return Object.keys(queryParams).sort(collate).reduce(function (result, key) {
    result[key] = queryParams[key];
    return result;
  }, {});
}

// Generate a unique id particular to this replication.
// Not guaranteed to align perfectly with CouchDB's rep ids.
function generateReplicationId(src, target, opts) {
  var docIds = opts.doc_ids ? opts.doc_ids.sort(collate) : '';
  var filterFun = opts.filter ? opts.filter.toString() : '';
  var queryParams = '';
  var filterViewName =  '';

  if (opts.filter && opts.query_params) {
    queryParams = JSON.stringify(sortObjectPropertiesByKey(opts.query_params));
  }

  if (opts.filter && opts.filter === '_view') {
    filterViewName = opts.view.toString();
  }

  return PouchPromise.all([src.id(), target.id()]).then(function (res) {
    var queryData = res[0] + res[1] + filterFun + filterViewName +
      queryParams + docIds;
    return new PouchPromise(function (resolve) {
      binaryMd5(queryData, resolve);
    });
  }).then(function (md5sum) {
    // can't use straight-up md5 alphabet, because
    // the char '/' is interpreted as being for attachments,
    // and + is also not url-safe
    md5sum = md5sum.replace(/\//g, '.').replace(/\+/g, '_');
    return '_local/' + md5sum;
  });
}

function replicate$1(src, target, opts, returnValue, result) {
  var batches = [];               // list of batches to be processed
  var currentBatch;               // the batch currently being processed
  var pendingBatch = {
    seq: 0,
    changes: [],
    docs: []
  }; // next batch, not yet ready to be processed
  var writingCheckpoint = false;  // true while checkpoint is being written
  var changesCompleted = false;   // true when all changes received
  var replicationCompleted = false; // true when replication has completed
  var last_seq = 0;
  var continuous = opts.continuous || opts.live || false;
  var batch_size = opts.batch_size || 100;
  var batches_limit = opts.batches_limit || 10;
  var changesPending = false;     // true while src.changes is running
  var doc_ids = opts.doc_ids;
  var repId;
  var checkpointer;
  var changedDocs = [];
  // Like couchdb, every replication gets a unique session id
  var session = uuid();

  result = result || {
    ok: true,
    start_time: new Date(),
    docs_read: 0,
    docs_written: 0,
    doc_write_failures: 0,
    errors: []
  };

  var changesOpts = {};
  returnValue.ready(src, target);

  function initCheckpointer() {
    if (checkpointer) {
      return PouchPromise.resolve();
    }
    return generateReplicationId(src, target, opts).then(function (res) {
      repId = res;
      checkpointer = new Checkpointer(src, target, repId, returnValue);
    });
  }

  function writeDocs() {
    changedDocs = [];

    if (currentBatch.docs.length === 0) {
      return;
    }
    var docs = currentBatch.docs;
    var bulkOpts = {timeout: opts.timeout};
    return target.bulkDocs({docs: docs, new_edits: false}, bulkOpts).then(function (res) {
      /* istanbul ignore if */
      if (returnValue.cancelled) {
        completeReplication();
        throw new Error('cancelled');
      }

      // `res` doesn't include full documents (which live in `docs`), so we create a map of 
      // (id -> error), and check for errors while iterating over `docs`
      var errorsById = Object.create(null);
      res.forEach(function (res) {
        if (res.error) {
          errorsById[res.id] = res;
        }
      });

      var errorsNo = Object.keys(errorsById).length;
      result.doc_write_failures += errorsNo;
      result.docs_written += docs.length - errorsNo;

      docs.forEach(function (doc) {
        var error = errorsById[doc._id];
        if (error) {
          result.errors.push(error);
          if (error.name === 'unauthorized' || error.name === 'forbidden') {
            returnValue.emit('denied', clone(error));
          } else {
            throw error;
          }
        } else {
          changedDocs.push(doc);
        }
      });

    }, function (err) {
      result.doc_write_failures += docs.length;
      throw err;
    });
  }

  function finishBatch() {
    if (currentBatch.error) {
      throw new Error('There was a problem getting docs.');
    }
    result.last_seq = last_seq = currentBatch.seq;
    var outResult = clone(result);
    if (changedDocs.length) {
      outResult.docs = changedDocs;
      returnValue.emit('change', outResult);
    }
    writingCheckpoint = true;
    return checkpointer.writeCheckpoint(currentBatch.seq,
        session).then(function () {
      writingCheckpoint = false;
      /* istanbul ignore if */
      if (returnValue.cancelled) {
        completeReplication();
        throw new Error('cancelled');
      }
      currentBatch = undefined;
      getChanges();
    }).catch(function (err) {
      onCheckpointError(err);
      throw err;
    });
  }

  function getDiffs() {
    var diff = {};
    currentBatch.changes.forEach(function (change) {
      // Couchbase Sync Gateway emits these, but we can ignore them
      /* istanbul ignore if */
      if (change.id === "_user/") {
        return;
      }
      diff[change.id] = change.changes.map(function (x) {
        return x.rev;
      });
    });
    return target.revsDiff(diff).then(function (diffs) {
      /* istanbul ignore if */
      if (returnValue.cancelled) {
        completeReplication();
        throw new Error('cancelled');
      }
      // currentBatch.diffs elements are deleted as the documents are written
      currentBatch.diffs = diffs;
    });
  }

  function getBatchDocs() {
    return getDocs(src, target, currentBatch.diffs, returnValue).then(function (got) {
      currentBatch.error = !got.ok;
      got.docs.forEach(function (doc) {
        delete currentBatch.diffs[doc._id];
        result.docs_read++;
        currentBatch.docs.push(doc);
      });
    });
  }

  function startNextBatch() {
    if (returnValue.cancelled || currentBatch) {
      return;
    }
    if (batches.length === 0) {
      processPendingBatch(true);
      return;
    }
    currentBatch = batches.shift();
    getDiffs()
      .then(getBatchDocs)
      .then(writeDocs)
      .then(finishBatch)
      .then(startNextBatch)
      .catch(function (err) {
        abortReplication('batch processing terminated with error', err);
      });
  }


  function processPendingBatch(immediate) {
    if (pendingBatch.changes.length === 0) {
      if (batches.length === 0 && !currentBatch) {
        if ((continuous && changesOpts.live) || changesCompleted) {
          returnValue.state = 'pending';
          returnValue.emit('paused');
        }
        if (changesCompleted) {
          completeReplication();
        }
      }
      return;
    }
    if (
      immediate ||
      changesCompleted ||
      pendingBatch.changes.length >= batch_size
    ) {
      batches.push(pendingBatch);
      pendingBatch = {
        seq: 0,
        changes: [],
        docs: []
      };
      if (returnValue.state === 'pending' || returnValue.state === 'stopped') {
        returnValue.state = 'active';
        returnValue.emit('active');
      }
      startNextBatch();
    }
  }


  function abortReplication(reason, err) {
    if (replicationCompleted) {
      return;
    }
    if (!err.message) {
      err.message = reason;
    }
    result.ok = false;
    result.status = 'aborting';
    batches = [];
    pendingBatch = {
      seq: 0,
      changes: [],
      docs: []
    };
    completeReplication(err);
  }


  function completeReplication(fatalError) {
    if (replicationCompleted) {
      return;
    }
    /* istanbul ignore if */
    if (returnValue.cancelled) {
      result.status = 'cancelled';
      if (writingCheckpoint) {
        return;
      }
    }
    result.status = result.status || 'complete';
    result.end_time = new Date();
    result.last_seq = last_seq;
    replicationCompleted = true;

    if (fatalError) {
      fatalError.result = result;

      if (fatalError.name === 'unauthorized' || fatalError.name === 'forbidden') {
        returnValue.emit('error', fatalError);
        returnValue.removeAllListeners();
      } else {
        backOff(opts, returnValue, fatalError, function () {
          replicate$1(src, target, opts, returnValue);
        });
      }
    } else {
      returnValue.emit('complete', result);
      returnValue.removeAllListeners();
    }
  }


  function onChange(change) {
    /* istanbul ignore if */
    if (returnValue.cancelled) {
      return completeReplication();
    }
    var filter = filterChange(opts)(change);
    if (!filter) {
      return;
    }
    pendingBatch.seq = change.seq;
    pendingBatch.changes.push(change);
    processPendingBatch(batches.length === 0 && changesOpts.live);
  }


  function onChangesComplete(changes) {
    changesPending = false;
    /* istanbul ignore if */
    if (returnValue.cancelled) {
      return completeReplication();
    }

    // if no results were returned then we're done,
    // else fetch more
    if (changes.results.length > 0) {
      changesOpts.since = changes.last_seq;
      getChanges();
      processPendingBatch(true);
    } else {

      var complete = function () {
        if (continuous) {
          changesOpts.live = true;
          getChanges();
        } else {
          changesCompleted = true;
        }
        processPendingBatch(true);
      };

      // update the checkpoint so we start from the right seq next time
      if (!currentBatch && changes.results.length === 0) {
        writingCheckpoint = true;
        checkpointer.writeCheckpoint(changes.last_seq,
            session).then(function () {
          writingCheckpoint = false;
          result.last_seq = last_seq = changes.last_seq;
          complete();
        })
        .catch(onCheckpointError);
      } else {
        complete();
      }
    }
  }


  function onChangesError(err) {
    changesPending = false;
    /* istanbul ignore if */
    if (returnValue.cancelled) {
      return completeReplication();
    }
    abortReplication('changes rejected', err);
  }


  function getChanges() {
    if (!(
      !changesPending &&
      !changesCompleted &&
      batches.length < batches_limit
      )) {
      return;
    }
    changesPending = true;
    function abortChanges() {
      changes.cancel();
    }
    function removeListener() {
      returnValue.removeListener('cancel', abortChanges);
    }

    if (returnValue._changes) { // remove old changes() and listeners
      returnValue.removeListener('cancel', returnValue._abortChanges);
      returnValue._changes.cancel();
    }
    returnValue.once('cancel', abortChanges);

    var changes = src.changes(changesOpts)
      .on('change', onChange);
    changes.then(removeListener, removeListener);
    changes.then(onChangesComplete)
      .catch(onChangesError);

    if (opts.retry) {
      // save for later so we can cancel if necessary
      returnValue._changes = changes;
      returnValue._abortChanges = abortChanges;
    }
  }


  function startChanges() {
    initCheckpointer().then(function () {
      /* istanbul ignore if */
      if (returnValue.cancelled) {
        completeReplication();
        return;
      }
      return checkpointer.getCheckpoint().then(function (checkpoint) {
        last_seq = checkpoint;
        changesOpts = {
          since: last_seq,
          limit: batch_size,
          batch_size: batch_size,
          style: 'all_docs',
          doc_ids: doc_ids,
          return_docs: true // required so we know when we're done
        };
        if (opts.filter) {
          if (typeof opts.filter !== 'string') {
            // required for the client-side filter in onChange
            changesOpts.include_docs = true;
          } else { // ddoc filter
            changesOpts.filter = opts.filter;
          }
        }
        if ('heartbeat' in opts) {
          changesOpts.heartbeat = opts.heartbeat;
        }
        if ('timeout' in opts) {
          changesOpts.timeout = opts.timeout;
        }
        if (opts.query_params) {
          changesOpts.query_params = opts.query_params;
        }
        if (opts.view) {
          changesOpts.view = opts.view;
        }
        getChanges();
      });
    }).catch(function (err) {
      abortReplication('getCheckpoint rejected with ', err);
    });
  }

  /* istanbul ignore next */
  function onCheckpointError(err) {
    writingCheckpoint = false;
    abortReplication('writeCheckpoint completed with error', err);
  }

  /* istanbul ignore if */
  if (returnValue.cancelled) { // cancelled immediately
    completeReplication();
    return;
  }

  if (!returnValue._addedListeners) {
    returnValue.once('cancel', completeReplication);

    if (typeof opts.complete === 'function') {
      returnValue.once('error', opts.complete);
      returnValue.once('complete', function (result) {
        opts.complete(null, result);
      });
    }
    returnValue._addedListeners = true;
  }

  if (typeof opts.since === 'undefined') {
    startChanges();
  } else {
    initCheckpointer().then(function () {
      writingCheckpoint = true;
      return checkpointer.writeCheckpoint(opts.since, session);
    }).then(function () {
      writingCheckpoint = false;
      /* istanbul ignore if */
      if (returnValue.cancelled) {
        completeReplication();
        return;
      }
      last_seq = opts.since;
      startChanges();
    }).catch(onCheckpointError);
  }
}

// We create a basic promise so the caller can cancel the replication possibly
// before we have actually started listening to changes etc
inherits(Replication, events.EventEmitter);
function Replication() {
  events.EventEmitter.call(this);
  this.cancelled = false;
  this.state = 'pending';
  var self = this;
  var promise = new PouchPromise(function (fulfill, reject) {
    self.once('complete', fulfill);
    self.once('error', reject);
  });
  self.then = function (resolve, reject) {
    return promise.then(resolve, reject);
  };
  self.catch = function (reject) {
    return promise.catch(reject);
  };
  // As we allow error handling via "error" event as well,
  // put a stub in here so that rejecting never throws UnhandledError.
  self.catch(function () {});
}

Replication.prototype.cancel = function () {
  this.cancelled = true;
  this.state = 'cancelled';
  this.emit('cancel');
};

Replication.prototype.ready = function (src, target) {
  var self = this;
  if (self._readyCalled) {
    return;
  }
  self._readyCalled = true;

  function onDestroy() {
    self.cancel();
  }
  src.once('destroyed', onDestroy);
  target.once('destroyed', onDestroy);
  function cleanup() {
    src.removeListener('destroyed', onDestroy);
    target.removeListener('destroyed', onDestroy);
  }
  self.once('complete', cleanup);
};

function toPouch(db, opts) {
  var PouchConstructor = opts.PouchConstructor;
  if (typeof db === 'string') {
    return new PouchConstructor(db, opts);
  } else {
    return db;
  }
}

function replicate(src, target, opts, callback) {

  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }
  if (typeof opts === 'undefined') {
    opts = {};
  }

  if (opts.doc_ids && !Array.isArray(opts.doc_ids)) {
    throw createError(BAD_REQUEST,
                       "`doc_ids` filter parameter is not a list.");
  }

  opts.complete = callback;
  opts = clone(opts);
  opts.continuous = opts.continuous || opts.live;
  opts.retry = ('retry' in opts) ? opts.retry : false;
  /*jshint validthis:true */
  opts.PouchConstructor = opts.PouchConstructor || this;
  var replicateRet = new Replication(opts);
  var srcPouch = toPouch(src, opts);
  var targetPouch = toPouch(target, opts);
  replicate$1(srcPouch, targetPouch, opts, replicateRet);
  return replicateRet;
}

inherits(Sync, events.EventEmitter);
function sync(src, target, opts, callback) {
  if (typeof opts === 'function') {
    callback = opts;
    opts = {};
  }
  if (typeof opts === 'undefined') {
    opts = {};
  }
  opts = clone(opts);
  /*jshint validthis:true */
  opts.PouchConstructor = opts.PouchConstructor || this;
  src = toPouch(src, opts);
  target = toPouch(target, opts);
  return new Sync(src, target, opts, callback);
}

function Sync(src, target, opts, callback) {
  var self = this;
  this.canceled = false;

  var optsPush = opts.push ? extend$1({}, opts, opts.push) : opts;
  var optsPull = opts.pull ? extend$1({}, opts, opts.pull) : opts;

  this.push = replicate(src, target, optsPush);
  this.pull = replicate(target, src, optsPull);

  this.pushPaused = true;
  this.pullPaused = true;

  function pullChange(change) {
    self.emit('change', {
      direction: 'pull',
      change: change
    });
  }
  function pushChange(change) {
    self.emit('change', {
      direction: 'push',
      change: change
    });
  }
  function pushDenied(doc) {
    self.emit('denied', {
      direction: 'push',
      doc: doc
    });
  }
  function pullDenied(doc) {
    self.emit('denied', {
      direction: 'pull',
      doc: doc
    });
  }
  function pushPaused() {
    self.pushPaused = true;
    /* istanbul ignore if */
    if (self.pullPaused) {
      self.emit('paused');
    }
  }
  function pullPaused() {
    self.pullPaused = true;
    /* istanbul ignore if */
    if (self.pushPaused) {
      self.emit('paused');
    }
  }
  function pushActive() {
    self.pushPaused = false;
    /* istanbul ignore if */
    if (self.pullPaused) {
      self.emit('active', {
        direction: 'push'
      });
    }
  }
  function pullActive() {
    self.pullPaused = false;
    /* istanbul ignore if */
    if (self.pushPaused) {
      self.emit('active', {
        direction: 'pull'
      });
    }
  }

  var removed = {};

  function removeAll(type) { // type is 'push' or 'pull'
    return function (event, func) {
      var isChange = event === 'change' &&
        (func === pullChange || func === pushChange);
      var isDenied = event === 'denied' &&
        (func === pullDenied || func === pushDenied);
      var isPaused = event === 'paused' &&
        (func === pullPaused || func === pushPaused);
      var isActive = event === 'active' &&
        (func === pullActive || func === pushActive);

      if (isChange || isDenied || isPaused || isActive) {
        if (!(event in removed)) {
          removed[event] = {};
        }
        removed[event][type] = true;
        if (Object.keys(removed[event]).length === 2) {
          // both push and pull have asked to be removed
          self.removeAllListeners(event);
        }
      }
    };
  }

  if (opts.live) {
    this.push.on('complete', self.pull.cancel.bind(self.pull));
    this.pull.on('complete', self.push.cancel.bind(self.push));
  }

  this.on('newListener', function (event) {
    if (event === 'change') {
      self.pull.on('change', pullChange);
      self.push.on('change', pushChange);
    } else if (event === 'denied') {
      self.pull.on('denied', pullDenied);
      self.push.on('denied', pushDenied);
    } else if (event === 'active') {
      self.pull.on('active', pullActive);
      self.push.on('active', pushActive);
    } else if (event === 'paused') {
      self.pull.on('paused', pullPaused);
      self.push.on('paused', pushPaused);
    }
  });

  this.on('removeListener', function (event) {
    if (event === 'change') {
      self.pull.removeListener('change', pullChange);
      self.push.removeListener('change', pushChange);
    } else if (event === 'denied') {
      self.pull.removeListener('denied', pullDenied);
      self.push.removeListener('denied', pushDenied);
    } else if (event === 'active') {
      self.pull.removeListener('active', pullActive);
      self.push.removeListener('active', pushActive);
    } else if (event === 'paused') {
      self.pull.removeListener('paused', pullPaused);
      self.push.removeListener('paused', pushPaused);
    }
  });

  this.pull.on('removeListener', removeAll('pull'));
  this.push.on('removeListener', removeAll('push'));

  var promise = PouchPromise.all([
    this.push,
    this.pull
  ]).then(function (resp) {
    var out = {
      push: resp[0],
      pull: resp[1]
    };
    self.emit('complete', out);
    if (callback) {
      callback(null, out);
    }
    self.removeAllListeners();
    return out;
  }, function (err) {
    self.cancel();
    if (callback) {
      // if there's a callback, then the callback can receive
      // the error event
      callback(err);
    } else {
      // if there's no callback, then we're safe to emit an error
      // event, which would otherwise throw an unhandled error
      // due to 'error' being a special event in EventEmitters
      self.emit('error', err);
    }
    self.removeAllListeners();
    if (callback) {
      // no sense throwing if we're already emitting an 'error' event
      throw err;
    }
  });

  this.then = function (success, err) {
    return promise.then(success, err);
  };

  this.catch = function (err) {
    return promise.catch(err);
  };
}

Sync.prototype.cancel = function () {
  if (!this.canceled) {
    this.canceled = true;
    this.push.cancel();
    this.pull.cancel();
  }
};

function replication(PouchDB) {
  PouchDB.replicate = replicate;
  PouchDB.sync = sync;

  Object.defineProperty(PouchDB.prototype, 'replicate', {
    get: function () {
      var self = this;
      return {
        from: function (other, opts, callback) {
          return self.constructor.replicate(other, self, opts, callback);
        },
        to: function (other, opts, callback) {
          return self.constructor.replicate(self, other, opts, callback);
        }
      };
    }
  });

  PouchDB.prototype.sync = function (dbName, opts, callback) {
    return this.constructor.sync(this, dbName, opts, callback);
  };
}

PouchDB.plugin(IDBPouch)
  .plugin(WebSqlPouch)
  .plugin(HttpPouch$1)
  .plugin(mapreduce)
  .plugin(replication);

module.exports = PouchDB;
}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"_process":113,"argsarray":5,"debug":8,"es6-promise-pool":22,"events":107,"inherits":28,"lie":40,"scope-eval":78,"spark-md5":79,"vuvuzela":100}],63:[function(require,module,exports){
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

// based on https://github.com/montagejs/collections
function mangle(key) {
  return '$' + key;
}
function unmangle(key) {
  return key.substring(1);
}
function LazyMap() {
  this.store = {};
}
LazyMap.prototype.get = function (key) {
  var mangled = mangle(key);
  return this.store[mangled];
};
LazyMap.prototype.set = function (key, value) {
  var mangled = mangle(key);
  this.store[mangled] = value;
  return true;
};
LazyMap.prototype.has = function (key) {
  var mangled = mangle(key);
  return mangled in this.store;
};
LazyMap.prototype.delete = function (key) {
  var mangled = mangle(key);
  var res = mangled in this.store;
  delete this.store[mangled];
  return res;
};
LazyMap.prototype.forEach = function (cb) {
  var keys = Object.keys(this.store);
  for (var i = 0, len = keys.length; i < len; i++) {
    var key = keys[i];
    var value = this.store[key];
    key = unmangle(key);
    cb(value, key);
  }
};

function LazySet(array) {
  this.store = new LazyMap();

  // init with an array
  if (array && Array.isArray(array)) {
    for (var i = 0, len = array.length; i < len; i++) {
      this.add(array[i]);
    }
  }
}
LazySet.prototype.add = function (key) {
  return this.store.set(key, true);
};
LazySet.prototype.has = function (key) {
  return this.store.has(key);
};

exports.Set = LazySet;
exports.Map = LazyMap;
},{}],64:[function(require,module,exports){
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var inherits = _interopDefault(require('inherits'));

inherits(PouchError, Error);

function PouchError(opts) {
  Error.call(this, opts.reason);
  this.status = opts.status;
  this.name = opts.error;
  this.message = opts.reason;
  this.error = true;
}

PouchError.prototype.toString = function () {
  return JSON.stringify({
    status: this.status,
    name: this.name,
    message: this.message,
    reason: this.reason
  });
};

var UNAUTHORIZED = new PouchError({
  status: 401,
  error: 'unauthorized',
  reason: "Name or password is incorrect."
});

var MISSING_BULK_DOCS = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: "Missing JSON list of 'docs'"
});

var MISSING_DOC = new PouchError({
  status: 404,
  error: 'not_found',
  reason: 'missing'
});

var REV_CONFLICT = new PouchError({
  status: 409,
  error: 'conflict',
  reason: 'Document update conflict'
});

var INVALID_ID = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: '_id field must contain a string'
});

var MISSING_ID = new PouchError({
  status: 412,
  error: 'missing_id',
  reason: '_id is required for puts'
});

var RESERVED_ID = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: 'Only reserved document ids may start with underscore.'
});

var NOT_OPEN = new PouchError({
  status: 412,
  error: 'precondition_failed',
  reason: 'Database not open'
});

var UNKNOWN_ERROR = new PouchError({
  status: 500,
  error: 'unknown_error',
  reason: 'Database encountered an unknown error'
});

var BAD_ARG = new PouchError({
  status: 500,
  error: 'badarg',
  reason: 'Some query argument is invalid'
});

var INVALID_REQUEST = new PouchError({
  status: 400,
  error: 'invalid_request',
  reason: 'Request was invalid'
});

var QUERY_PARSE_ERROR = new PouchError({
  status: 400,
  error: 'query_parse_error',
  reason: 'Some query parameter is invalid'
});

var DOC_VALIDATION = new PouchError({
  status: 500,
  error: 'doc_validation',
  reason: 'Bad special document member'
});

var BAD_REQUEST = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: 'Something wrong with the request'
});

var NOT_AN_OBJECT = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: 'Document must be a JSON object'
});

var DB_MISSING = new PouchError({
  status: 404,
  error: 'not_found',
  reason: 'Database not found'
});

var IDB_ERROR = new PouchError({
  status: 500,
  error: 'indexed_db_went_bad',
  reason: 'unknown'
});

var WSQ_ERROR = new PouchError({
  status: 500,
  error: 'web_sql_went_bad',
  reason: 'unknown'
});

var LDB_ERROR = new PouchError({
  status: 500,
  error: 'levelDB_went_went_bad',
  reason: 'unknown'
});

var FORBIDDEN = new PouchError({
  status: 403,
  error: 'forbidden',
  reason: 'Forbidden by design doc validate_doc_update function'
});

var INVALID_REV = new PouchError({
  status: 400,
  error: 'bad_request',
  reason: 'Invalid rev format'
});

var FILE_EXISTS = new PouchError({
  status: 412,
  error: 'file_exists',
  reason: 'The database could not be created, the file already exists.'
});

var MISSING_STUB = new PouchError({
  status: 412,
  error: 'missing_stub'
});

var INVALID_URL = new PouchError({
  status: 413,
  error: 'invalid_url',
  reason: 'Provided URL is invalid'
});

function createError(error, reason) {
  function CustomPouchError(reason) {
    // inherit error properties from our parent error manually
    // so as to allow proper JSON parsing.
    /* jshint ignore:start */
    for (var p in error) {
      if (typeof error[p] !== 'function') {
        this[p] = error[p];
      }
    }
    /* jshint ignore:end */
    if (reason !== undefined) {
      this.reason = reason;
    }
  }
  CustomPouchError.prototype = PouchError.prototype;
  return new CustomPouchError(reason);
}

function generateErrorFromResponse(err) {

  if (typeof err !== 'object') {
    var data = err;
    err = UNKNOWN_ERROR;
    err.data = data;
  }

  if ('error' in err && err.error === 'conflict') {
    err.name = 'conflict';
    err.status = 409;
  }

  if (!('name' in err)) {
    err.name = err.error || 'unknown';
  }

  if (!('status' in err)) {
    err.status = 500;
  }

  if (!('message' in err)) {
    err.message = err.message || err.reason;
  }

  return err;
}

exports.UNAUTHORIZED = UNAUTHORIZED;
exports.MISSING_BULK_DOCS = MISSING_BULK_DOCS;
exports.MISSING_DOC = MISSING_DOC;
exports.REV_CONFLICT = REV_CONFLICT;
exports.INVALID_ID = INVALID_ID;
exports.MISSING_ID = MISSING_ID;
exports.RESERVED_ID = RESERVED_ID;
exports.NOT_OPEN = NOT_OPEN;
exports.UNKNOWN_ERROR = UNKNOWN_ERROR;
exports.BAD_ARG = BAD_ARG;
exports.INVALID_REQUEST = INVALID_REQUEST;
exports.QUERY_PARSE_ERROR = QUERY_PARSE_ERROR;
exports.DOC_VALIDATION = DOC_VALIDATION;
exports.BAD_REQUEST = BAD_REQUEST;
exports.NOT_AN_OBJECT = NOT_AN_OBJECT;
exports.DB_MISSING = DB_MISSING;
exports.WSQ_ERROR = WSQ_ERROR;
exports.LDB_ERROR = LDB_ERROR;
exports.FORBIDDEN = FORBIDDEN;
exports.INVALID_REV = INVALID_REV;
exports.FILE_EXISTS = FILE_EXISTS;
exports.MISSING_STUB = MISSING_STUB;
exports.IDB_ERROR = IDB_ERROR;
exports.INVALID_URL = INVALID_URL;
exports.createError = createError;
exports.generateErrorFromResponse = generateErrorFromResponse;
},{"inherits":28}],65:[function(require,module,exports){
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var vuvuzela = _interopDefault(require('vuvuzela'));

function slowJsonParse(str) {
  try {
    return JSON.parse(str);
  } catch (e) {
    /* istanbul ignore next */
    return vuvuzela.parse(str);
  }
}

function safeJsonParse(str) {
  // try/catch is deoptimized in V8, leading to slower
  // times than we'd like to have. Most documents are _not_
  // huge, and do not require a slower code path just to parse them.
  // We can be pretty sure that a document under 50000 characters
  // will not be so deeply nested as to throw a stack overflow error
  // (depends on the engine and available memory, though, so this is
  // just a hunch). 50000 was chosen based on the average length
  // of this string in our test suite, to try to find a number that covers
  // most of our test cases (26 over this size, 26378 under it).
  if (str.length < 50000) {
    return JSON.parse(str);
  }
  return slowJsonParse(str);
}

function safeJsonStringify(json) {
  try {
    return JSON.stringify(json);
  } catch (e) {
    /* istanbul ignore next */
    return vuvuzela.stringify(json);
  }
}

exports.safeJsonParse = safeJsonParse;
exports.safeJsonStringify = safeJsonStringify;
},{"vuvuzela":100}],66:[function(require,module,exports){
(function (global){
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var pouchdbBinaryUtils = require('pouchdb-binary-utils');
var Md5 = _interopDefault(require('spark-md5'));

var setImmediateShim = global.setImmediate || global.setTimeout;
var MD5_CHUNK_SIZE = 32768;

function rawToBase64(raw) {
  return pouchdbBinaryUtils.btoa(raw);
}

function sliceBlob(blob, start, end) {
  if (blob.webkitSlice) {
    return blob.webkitSlice(start, end);
  }
  return blob.slice(start, end);
}

function appendBlob(buffer, blob, start, end, callback) {
  if (start > 0 || end < blob.size) {
    // only slice blob if we really need to
    blob = sliceBlob(blob, start, end);
  }
  pouchdbBinaryUtils.readAsArrayBuffer(blob, function (arrayBuffer) {
    buffer.append(arrayBuffer);
    callback();
  });
}

function appendString(buffer, string, start, end, callback) {
  if (start > 0 || end < string.length) {
    // only create a substring if we really need to
    string = string.substring(start, end);
  }
  buffer.appendBinary(string);
  callback();
}

function binaryMd5(data, callback) {
  var inputIsString = typeof data === 'string';
  var len = inputIsString ? data.length : data.size;
  var chunkSize = Math.min(MD5_CHUNK_SIZE, len);
  var chunks = Math.ceil(len / chunkSize);
  var currentChunk = 0;
  var buffer = inputIsString ? new Md5() : new Md5.ArrayBuffer();

  var append = inputIsString ? appendString : appendBlob;

  function next() {
    setImmediateShim(loadNextChunk);
  }

  function done() {
    var raw = buffer.end(true);
    var base64 = rawToBase64(raw);
    callback(base64);
    buffer.destroy();
  }

  function loadNextChunk() {
    var start = currentChunk * chunkSize;
    var end = start + chunkSize;
    currentChunk++;
    if (currentChunk < chunks) {
      append(buffer, data, start, end, next);
    } else {
      append(buffer, data, start, end, done);
    }
  }
  loadNextChunk();
}

function stringMd5(string) {
  return Md5.hash(string);
}

exports.binaryMd5 = binaryMd5;
exports.stringMd5 = stringMd5;
}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"pouchdb-binary-utils":61,"spark-md5":79}],67:[function(require,module,exports){
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

// We fetch all leafs of the revision tree, and sort them based on tree length
// and whether they were deleted, undeleted documents with the longest revision
// tree (most edits) win
// The final sort algorithm is slightly documented in a sidebar here:
// http://guide.couchdb.org/draft/conflicts.html
function winningRev(metadata) {
  var winningId;
  var winningPos;
  var winningDeleted;
  var toVisit = metadata.rev_tree.slice();
  var node;
  while ((node = toVisit.pop())) {
    var tree = node.ids;
    var branches = tree[2];
    var pos = node.pos;
    if (branches.length) { // non-leaf
      for (var i = 0, len = branches.length; i < len; i++) {
        toVisit.push({pos: pos + 1, ids: branches[i]});
      }
      continue;
    }
    var deleted = !!tree[1].deleted;
    var id = tree[0];
    // sort by deleted, then pos, then id
    if (!winningId || (winningDeleted !== deleted ? winningDeleted :
        winningPos !== pos ? winningPos < pos : winningId < id)) {
      winningId = id;
      winningPos = pos;
      winningDeleted = deleted;
    }
  }

  return winningPos + '-' + winningId;
}

// Pretty much all below can be combined into a higher order function to
// traverse revisions
// The return value from the callback will be passed as context to all
// children of that node
function traverseRevTree(revs, callback) {
  var toVisit = revs.slice();

  var node;
  while ((node = toVisit.pop())) {
    var pos = node.pos;
    var tree = node.ids;
    var branches = tree[2];
    var newCtx =
      callback(branches.length === 0, pos, tree[0], node.ctx, tree[1]);
    for (var i = 0, len = branches.length; i < len; i++) {
      toVisit.push({pos: pos + 1, ids: branches[i], ctx: newCtx});
    }
  }
}

function sortByPos(a, b) {
  return a.pos - b.pos;
}

function collectLeaves(revs) {
  var leaves = [];
  traverseRevTree(revs, function (isLeaf, pos, id, acc, opts) {
    if (isLeaf) {
      leaves.push({rev: pos + "-" + id, pos: pos, opts: opts});
    }
  });
  leaves.sort(sortByPos).reverse();
  for (var i = 0, len = leaves.length; i < len; i++) {
    delete leaves[i].pos;
  }
  return leaves;
}

// returns revs of all conflicts that is leaves such that
// 1. are not deleted and
// 2. are different than winning revision
function collectConflicts(metadata) {
  var win = winningRev(metadata);
  var leaves = collectLeaves(metadata.rev_tree);
  var conflicts = [];
  for (var i = 0, len = leaves.length; i < len; i++) {
    var leaf = leaves[i];
    if (leaf.rev !== win && !leaf.opts.deleted) {
      conflicts.push(leaf.rev);
    }
  }
  return conflicts;
}

// compact a tree by marking its non-leafs as missing,
// and return a list of revs to delete
function compactTree(metadata) {
  var revs = [];
  traverseRevTree(metadata.rev_tree, function (isLeaf, pos,
                                               revHash, ctx, opts) {
    if (opts.status === 'available' && !isLeaf) {
      revs.push(pos + '-' + revHash);
      opts.status = 'missing';
    }
  });
  return revs;
}

// build up a list of all the paths to the leafs in this revision tree
function rootToLeaf(revs) {
  var paths = [];
  var toVisit = revs.slice();
  var node;
  while ((node = toVisit.pop())) {
    var pos = node.pos;
    var tree = node.ids;
    var id = tree[0];
    var opts = tree[1];
    var branches = tree[2];
    var isLeaf = branches.length === 0;

    var history = node.history ? node.history.slice() : [];
    history.push({id: id, opts: opts});
    if (isLeaf) {
      paths.push({pos: (pos + 1 - history.length), ids: history});
    }
    for (var i = 0, len = branches.length; i < len; i++) {
      toVisit.push({pos: pos + 1, ids: branches[i], history: history});
    }
  }
  return paths.reverse();
}

// for a better overview of what this is doing, read:
// https://github.com/apache/couchdb-couch/blob/master/src/couch_key_tree.erl
//
// But for a quick intro, CouchDB uses a revision tree to store a documents
// history, A -> B -> C, when a document has conflicts, that is a branch in the
// tree, A -> (B1 | B2 -> C), We store these as a nested array in the format
//
// KeyTree = [Path ... ]
// Path = {pos: position_from_root, ids: Tree}
// Tree = [Key, Opts, [Tree, ...]], in particular single node: [Key, []]

function sortByPos$1(a, b) {
  return a.pos - b.pos;
}

// classic binary search
function binarySearch(arr, item, comparator) {
  var low = 0;
  var high = arr.length;
  var mid;
  while (low < high) {
    mid = (low + high) >>> 1;
    if (comparator(arr[mid], item) < 0) {
      low = mid + 1;
    } else {
      high = mid;
    }
  }
  return low;
}

// assuming the arr is sorted, insert the item in the proper place
function insertSorted(arr, item, comparator) {
  var idx = binarySearch(arr, item, comparator);
  arr.splice(idx, 0, item);
}

// Turn a path as a flat array into a tree with a single branch.
// If any should be stemmed from the beginning of the array, that's passed
// in as the second argument
function pathToTree(path, numStemmed) {
  var root;
  var leaf;
  for (var i = numStemmed, len = path.length; i < len; i++) {
    var node = path[i];
    var currentLeaf = [node.id, node.opts, []];
    if (leaf) {
      leaf[2].push(currentLeaf);
      leaf = currentLeaf;
    } else {
      root = leaf = currentLeaf;
    }
  }
  return root;
}

// compare the IDs of two trees
function compareTree(a, b) {
  return a[0] < b[0] ? -1 : 1;
}

// Merge two trees together
// The roots of tree1 and tree2 must be the same revision
function mergeTree(in_tree1, in_tree2) {
  var queue = [{tree1: in_tree1, tree2: in_tree2}];
  var conflicts = false;
  while (queue.length > 0) {
    var item = queue.pop();
    var tree1 = item.tree1;
    var tree2 = item.tree2;

    if (tree1[1].status || tree2[1].status) {
      tree1[1].status =
        (tree1[1].status ===  'available' ||
        tree2[1].status === 'available') ? 'available' : 'missing';
    }

    for (var i = 0; i < tree2[2].length; i++) {
      if (!tree1[2][0]) {
        conflicts = 'new_leaf';
        tree1[2][0] = tree2[2][i];
        continue;
      }

      var merged = false;
      for (var j = 0; j < tree1[2].length; j++) {
        if (tree1[2][j][0] === tree2[2][i][0]) {
          queue.push({tree1: tree1[2][j], tree2: tree2[2][i]});
          merged = true;
        }
      }
      if (!merged) {
        conflicts = 'new_branch';
        insertSorted(tree1[2], tree2[2][i], compareTree);
      }
    }
  }
  return {conflicts: conflicts, tree: in_tree1};
}

function doMerge(tree, path, dontExpand) {
  var restree = [];
  var conflicts = false;
  var merged = false;
  var res;

  if (!tree.length) {
    return {tree: [path], conflicts: 'new_leaf'};
  }

  for (var i = 0, len = tree.length; i < len; i++) {
    var branch = tree[i];
    if (branch.pos === path.pos && branch.ids[0] === path.ids[0]) {
      // Paths start at the same position and have the same root, so they need
      // merged
      res = mergeTree(branch.ids, path.ids);
      restree.push({pos: branch.pos, ids: res.tree});
      conflicts = conflicts || res.conflicts;
      merged = true;
    } else if (dontExpand !== true) {
      // The paths start at a different position, take the earliest path and
      // traverse up until it as at the same point from root as the path we
      // want to merge.  If the keys match we return the longer path with the
      // other merged After stemming we dont want to expand the trees

      var t1 = branch.pos < path.pos ? branch : path;
      var t2 = branch.pos < path.pos ? path : branch;
      var diff = t2.pos - t1.pos;

      var candidateParents = [];

      var trees = [];
      trees.push({ids: t1.ids, diff: diff, parent: null, parentIdx: null});
      while (trees.length > 0) {
        var item = trees.pop();
        if (item.diff === 0) {
          if (item.ids[0] === t2.ids[0]) {
            candidateParents.push(item);
          }
          continue;
        }
        var elements = item.ids[2];
        for (var j = 0, elementsLen = elements.length; j < elementsLen; j++) {
          trees.push({
            ids: elements[j],
            diff: item.diff - 1,
            parent: item.ids,
            parentIdx: j
          });
        }
      }

      var el = candidateParents[0];

      if (!el) {
        restree.push(branch);
      } else {
        res = mergeTree(el.ids, t2.ids);
        el.parent[2][el.parentIdx] = res.tree;
        restree.push({pos: t1.pos, ids: t1.ids});
        conflicts = conflicts || res.conflicts;
        merged = true;
      }
    } else {
      restree.push(branch);
    }
  }

  // We didnt find
  if (!merged) {
    restree.push(path);
  }

  restree.sort(sortByPos$1);

  return {
    tree: restree,
    conflicts: conflicts || 'internal_node'
  };
}

// To ensure we dont grow the revision tree infinitely, we stem old revisions
function stem(tree, depth) {
  // First we break out the tree into a complete list of root to leaf paths
  var paths = rootToLeaf(tree);
  var maybeStem = {};

  var result;
  for (var i = 0, len = paths.length; i < len; i++) {
    // Then for each path, we cut off the start of the path based on the
    // `depth` to stem to, and generate a new set of flat trees
    var path = paths[i];
    var stemmed = path.ids;
    var numStemmed = Math.max(0, stemmed.length - depth);
    var stemmedNode = {
      pos: path.pos + numStemmed,
      ids: pathToTree(stemmed, numStemmed)
    };

    for (var s = 0; s < numStemmed; s++) {
      var rev = (path.pos + s) + '-' + stemmed[s].id;
      maybeStem[rev] = true;
    }

    // Then we remerge all those flat trees together, ensuring that we dont
    // connect trees that would go beyond the depth limit
    if (result) {
      result = doMerge(result, stemmedNode, true).tree;
    } else {
      result = [stemmedNode];
    }
  }

  traverseRevTree(result, function (isLeaf, pos, revHash) {
    // some revisions may have been removed in a branch but not in another
    delete maybeStem[pos + '-' + revHash];
  });

  return {
    tree: result,
    revs: Object.keys(maybeStem)
  };
}

function merge(tree, path, depth) {
  var newTree = doMerge(tree, path);
  var stemmed = stem(newTree.tree, depth);
  return {
    tree: stemmed.tree,
    stemmedRevs: stemmed.revs,
    conflicts: newTree.conflicts
  };
}

// return true if a rev exists in the rev tree, false otherwise
function revExists(revs, rev) {
  var toVisit = revs.slice();
  var splitRev = rev.split('-');
  var targetPos = parseInt(splitRev[0], 10);
  var targetId = splitRev[1];

  var node;
  while ((node = toVisit.pop())) {
    if (node.pos === targetPos && node.ids[0] === targetId) {
      return true;
    }
    var branches = node.ids[2];
    for (var i = 0, len = branches.length; i < len; i++) {
      toVisit.push({pos: node.pos + 1, ids: branches[i]});
    }
  }
  return false;
}

function getTrees(node) {
  return node.ids;
}

// check if a specific revision of a doc has been deleted
//  - metadata: the metadata object from the doc store
//  - rev: (optional) the revision to check. defaults to winning revision
function isDeleted(metadata, rev) {
  if (!rev) {
    rev = winningRev(metadata);
  }
  var id = rev.substring(rev.indexOf('-') + 1);
  var toVisit = metadata.rev_tree.map(getTrees);

  var tree;
  while ((tree = toVisit.pop())) {
    if (tree[0] === id) {
      return !!tree[1].deleted;
    }
    toVisit = toVisit.concat(tree[2]);
  }
}

function isLocalId(id) {
  return (/^_local/).test(id);
}

exports.collectConflicts = collectConflicts;
exports.collectLeaves = collectLeaves;
exports.compactTree = compactTree;
exports.isDeleted = isDeleted;
exports.isLocalId = isLocalId;
exports.merge = merge;
exports.revExists = revExists;
exports.rootToLeaf = rootToLeaf;
exports.traverseRevTree = traverseRevTree;
exports.winningRev = winningRev;
},{}],68:[function(require,module,exports){
'use strict';

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var lie = _interopDefault(require('lie'));

/* istanbul ignore next */
var PouchPromise = typeof Promise === 'function' ? Promise : lie;

module.exports = PouchPromise;
},{"lie":40}],69:[function(require,module,exports){
(function (process){
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var Promise = _interopDefault(require('pouchdb-promise'));
var getArguments = _interopDefault(require('argsarray'));
var debug = _interopDefault(require('debug'));
var events = require('events');
var inherits = _interopDefault(require('inherits'));
var pouchdbErrors = require('pouchdb-errors');

function isBinaryObject(object) {
  return (typeof ArrayBuffer !== 'undefined' && object instanceof ArrayBuffer) ||
    (typeof Blob !== 'undefined' && object instanceof Blob);
}

function cloneArrayBuffer(buff) {
  if (typeof buff.slice === 'function') {
    return buff.slice(0);
  }
  // IE10-11 slice() polyfill
  var target = new ArrayBuffer(buff.byteLength);
  var targetArray = new Uint8Array(target);
  var sourceArray = new Uint8Array(buff);
  targetArray.set(sourceArray);
  return target;
}

function cloneBinaryObject(object) {
  if (object instanceof ArrayBuffer) {
    return cloneArrayBuffer(object);
  }
  var size = object.size;
  var type = object.type;
  // Blob
  if (typeof object.slice === 'function') {
    return object.slice(0, size, type);
  }
  // PhantomJS slice() replacement
  return object.webkitSlice(0, size, type);
}

// most of this is borrowed from lodash.isPlainObject:
// https://github.com/fis-components/lodash.isplainobject/
// blob/29c358140a74f252aeb08c9eb28bef86f2217d4a/index.js

var funcToString = Function.prototype.toString;
var objectCtorString = funcToString.call(Object);

function isPlainObject(value) {
  var proto = Object.getPrototypeOf(value);
  /* istanbul ignore if */
  if (proto === null) { // not sure when this happens, but I guess it can
    return true;
  }
  var Ctor = proto.constructor;
  return (typeof Ctor == 'function' &&
    Ctor instanceof Ctor && funcToString.call(Ctor) == objectCtorString);
}

function clone(object) {
  var newObject;
  var i;
  var len;

  if (!object || typeof object !== 'object') {
    return object;
  }

  if (Array.isArray(object)) {
    newObject = [];
    for (i = 0, len = object.length; i < len; i++) {
      newObject[i] = clone(object[i]);
    }
    return newObject;
  }

  // special case: to avoid inconsistencies between IndexedDB
  // and other backends, we automatically stringify Dates
  if (object instanceof Date) {
    return object.toISOString();
  }

  if (isBinaryObject(object)) {
    return cloneBinaryObject(object);
  }

  if (!isPlainObject(object)) {
    return object; // don't clone objects like Workers
  }

  newObject = {};
  for (i in object) {
    /* istanbul ignore else */
    if (Object.prototype.hasOwnProperty.call(object, i)) {
      var value = clone(object[i]);
      if (typeof value !== 'undefined') {
        newObject[i] = value;
      }
    }
  }
  return newObject;
}

function once(fun) {
  var called = false;
  return getArguments(function (args) {
    /* istanbul ignore if */
    if (called) {
      // this is a smoke test and should never actually happen
      throw new Error('once called more than once');
    } else {
      called = true;
      fun.apply(this, args);
    }
  });
}

function toPromise(func) {
  //create the function we will be returning
  return getArguments(function (args) {
    // Clone arguments
    args = clone(args);
    var self = this;
    var tempCB =
      (typeof args[args.length - 1] === 'function') ? args.pop() : false;
    // if the last argument is a function, assume its a callback
    var usedCB;
    if (tempCB) {
      // if it was a callback, create a new callback which calls it,
      // but do so async so we don't trap any errors
      usedCB = function (err, resp) {
        process.nextTick(function () {
          tempCB(err, resp);
        });
      };
    }
    var promise = new Promise(function (fulfill, reject) {
      var resp;
      try {
        var callback = once(function (err, mesg) {
          if (err) {
            reject(err);
          } else {
            fulfill(mesg);
          }
        });
        // create a callback for this invocation
        // apply the function in the orig context
        args.push(callback);
        resp = func.apply(self, args);
        if (resp && typeof resp.then === 'function') {
          fulfill(resp);
        }
      } catch (e) {
        reject(e);
      }
    });
    // if there is a callback, call it back
    if (usedCB) {
      promise.then(function (result) {
        usedCB(null, result);
      }, usedCB);
    }
    return promise;
  });
}

var log = debug('pouchdb:api');

function adapterFun(name, callback) {
  function logApiCall(self, name, args) {
    /* istanbul ignore if */
    if (log.enabled) {
      var logArgs = [self.name, name];
      for (var i = 0; i < args.length - 1; i++) {
        logArgs.push(args[i]);
      }
      log.apply(null, logArgs);

      // override the callback itself to log the response
      var origCallback = args[args.length - 1];
      args[args.length - 1] = function (err, res) {
        var responseArgs = [self.name, name];
        responseArgs = responseArgs.concat(
          err ? ['error', err] : ['success', res]
        );
        log.apply(null, responseArgs);
        origCallback(err, res);
      };
    }
  }

  return toPromise(getArguments(function (args) {
    if (this._closed) {
      return Promise.reject(new Error('database is closed'));
    }
    if (this._destroyed) {
      return Promise.reject(new Error('database is destroyed'));
    }
    var self = this;
    logApiCall(self, name, args);
    if (!this.taskqueue.isReady) {
      return new Promise(function (fulfill, reject) {
        self.taskqueue.addTask(function (failed) {
          if (failed) {
            reject(failed);
          } else {
            fulfill(self[name].apply(self, args));
          }
        });
      });
    }
    return callback.apply(this, args);
  }));
}

// like underscore/lodash _.pick()
function pick(obj, arr) {
  var res = {};
  for (var i = 0, len = arr.length; i < len; i++) {
    var prop = arr[i];
    if (prop in obj) {
      res[prop] = obj[prop];
    }
  }
  return res;
}

// Most browsers throttle concurrent requests at 6, so it's silly
// to shim _bulk_get by trying to launch potentially hundreds of requests
// and then letting the majority time out. We can handle this ourselves.
var MAX_NUM_CONCURRENT_REQUESTS = 6;

function identityFunction(x) {
  return x;
}

function formatResultForOpenRevsGet(result) {
  return [{
    ok: result
  }];
}

// shim for P/CouchDB adapters that don't directly implement _bulk_get
function bulkGet(db, opts, callback) {
  var requests = opts.docs;

  // consolidate into one request per doc if possible
  var requestsById = {};
  requests.forEach(function (request) {
    if (request.id in requestsById) {
      requestsById[request.id].push(request);
    } else {
      requestsById[request.id] = [request];
    }
  });

  var numDocs = Object.keys(requestsById).length;
  var numDone = 0;
  var perDocResults = new Array(numDocs);

  function collapseResultsAndFinish() {
    var results = [];
    perDocResults.forEach(function (res) {
      res.docs.forEach(function (info) {
        results.push({
          id: res.id,
          docs: [info]
        });
      });
    });
    callback(null, {results: results});
  }

  function checkDone() {
    if (++numDone === numDocs) {
      collapseResultsAndFinish();
    }
  }

  function gotResult(docIndex, id, docs) {
    perDocResults[docIndex] = {id: id, docs: docs};
    checkDone();
  }

  var allRequests = Object.keys(requestsById);

  var i = 0;

  function nextBatch() {

    if (i >= allRequests.length) {
      return;
    }

    var upTo = Math.min(i + MAX_NUM_CONCURRENT_REQUESTS, allRequests.length);
    var batch = allRequests.slice(i, upTo);
    processBatch(batch, i);
    i += batch.length;
  }

  function processBatch(batch, offset) {
    batch.forEach(function (docId, j) {
      var docIdx = offset + j;
      var docRequests = requestsById[docId];

      // just use the first request as the "template"
      // TODO: The _bulk_get API allows for more subtle use cases than this,
      // but for now it is unlikely that there will be a mix of different
      // "atts_since" or "attachments" in the same request, since it's just
      // replicate.js that is using this for the moment.
      // Also, atts_since is aspirational, since we don't support it yet.
      var docOpts = pick(docRequests[0], ['atts_since', 'attachments']);
      docOpts.open_revs = docRequests.map(function (request) {
        // rev is optional, open_revs disallowed
        return request.rev;
      });

      // remove falsey / undefined revisions
      docOpts.open_revs = docOpts.open_revs.filter(identityFunction);

      var formatResult = identityFunction;

      if (docOpts.open_revs.length === 0) {
        delete docOpts.open_revs;

        // when fetching only the "winning" leaf,
        // transform the result so it looks like an open_revs
        // request
        formatResult = formatResultForOpenRevsGet;
      }

      // globally-supplied options
      ['revs', 'attachments', 'binary', 'ajax'].forEach(function (param) {
        if (param in opts) {
          docOpts[param] = opts[param];
        }
      });
      db.get(docId, docOpts, function (err, res) {
        var result;
        /* istanbul ignore if */
        if (err) {
          result = [{error: err}];
        } else {
          result = formatResult(res);
        }
        gotResult(docIdx, docId, result);
        nextBatch();
      });
    });
  }

  nextBatch();

}

function isChromeApp() {
  return (typeof chrome !== "undefined" &&
    typeof chrome.storage !== "undefined" &&
    typeof chrome.storage.local !== "undefined");
}

var hasLocal;

if (isChromeApp()) {
  hasLocal = false;
} else {
  try {
    localStorage.setItem('_pouch_check_localstorage', 1);
    hasLocal = !!localStorage.getItem('_pouch_check_localstorage');
  } catch (e) {
    hasLocal = false;
  }
}

function hasLocalStorage() {
  return hasLocal;
}

inherits(Changes, events.EventEmitter);

/* istanbul ignore next */
function attachBrowserEvents(self) {
  if (isChromeApp()) {
    chrome.storage.onChanged.addListener(function (e) {
      // make sure it's event addressed to us
      if (e.db_name != null) {
        //object only has oldValue, newValue members
        self.emit(e.dbName.newValue);
      }
    });
  } else if (hasLocalStorage()) {
    if (typeof addEventListener !== 'undefined') {
      addEventListener("storage", function (e) {
        self.emit(e.key);
      });
    } else { // old IE
      window.attachEvent("storage", function (e) {
        self.emit(e.key);
      });
    }
  }
}

function Changes() {
  events.EventEmitter.call(this);
  this._listeners = {};

  attachBrowserEvents(this);
}
Changes.prototype.addListener = function (dbName, id, db, opts) {
  /* istanbul ignore if */
  if (this._listeners[id]) {
    return;
  }
  var self = this;
  var inprogress = false;
  function eventFunction() {
    /* istanbul ignore if */
    if (!self._listeners[id]) {
      return;
    }
    if (inprogress) {
      inprogress = 'waiting';
      return;
    }
    inprogress = true;
    var changesOpts = pick(opts, [
      'style', 'include_docs', 'attachments', 'conflicts', 'filter',
      'doc_ids', 'view', 'since', 'query_params', 'binary'
    ]);

    /* istanbul ignore next */
    function onError() {
      inprogress = false;
    }

    db.changes(changesOpts).on('change', function (c) {
      if (c.seq > opts.since && !opts.cancelled) {
        opts.since = c.seq;
        opts.onChange(c);
      }
    }).on('complete', function () {
      if (inprogress === 'waiting') {
        setTimeout(function (){
          eventFunction();
        },0);
      }
      inprogress = false;
    }).on('error', onError);
  }
  this._listeners[id] = eventFunction;
  this.on(dbName, eventFunction);
};

Changes.prototype.removeListener = function (dbName, id) {
  /* istanbul ignore if */
  if (!(id in this._listeners)) {
    return;
  }
  events.EventEmitter.prototype.removeListener.call(this, dbName,
    this._listeners[id]);
  delete this._listeners[id];
};


/* istanbul ignore next */
Changes.prototype.notifyLocalWindows = function (dbName) {
  //do a useless change on a storage thing
  //in order to get other windows's listeners to activate
  if (isChromeApp()) {
    chrome.storage.local.set({dbName: dbName});
  } else if (hasLocalStorage()) {
    localStorage[dbName] = (localStorage[dbName] === "a") ? "b" : "a";
  }
};

Changes.prototype.notify = function (dbName) {
  this.emit(dbName);
  this.notifyLocalWindows(dbName);
};

function guardedConsole(method) {
  /* istanbul ignore else */
  if (console !== 'undefined' && method in console) {
    var args = Array.prototype.slice.call(arguments, 1);
    console[method].apply(console, args);
  }
}

function randomNumber(min, max) {
  var maxTimeout = 600000; // Hard-coded default of 10 minutes
  min = parseInt(min, 10) || 0;
  max = parseInt(max, 10);
  if (max !== max || max <= min) {
    max = (min || 1) << 1; //doubling
  } else {
    max = max + 1;
  }
  // In order to not exceed maxTimeout, pick a random value between half of maxTimeout and maxTimeout
  if(max > maxTimeout) {
    min = maxTimeout >> 1; // divide by two
    max = maxTimeout;
  }
  var ratio = Math.random();
  var range = max - min;

  return ~~(range * ratio + min); // ~~ coerces to an int, but fast.
}

function defaultBackOff(min) {
  var max = 0;
  if (!min) {
    max = 2000;
  }
  return randomNumber(min, max);
}

// designed to give info to browser users, who are disturbed
// when they see http errors in the console
function explainError(status, str) {
  guardedConsole('info', 'The above ' + status + ' is totally normal. ' + str);
}

function extendInner(obj, otherObj) {
  for (var key in otherObj) {
    if (otherObj.hasOwnProperty(key)) {
      var value = clone(otherObj[key]);
      if (typeof value !== 'undefined') {
        obj[key] = value;
      }
    }
  }
}

function extend(obj, obj2, obj3) {
  extendInner(obj, obj2);
  if (obj3) {
    extendInner(obj, obj3);
  }
  return obj;
}

// forked from
// https://github.com/vmattos/js-extend/blob/7023fd69a9e9552688086b8b8006b1fcf916a306/extend.js
// TODO: I don't know why we have two different extend() functions in PouchDB

var slice = Array.prototype.slice;
var each = Array.prototype.forEach;

function extend$1(obj) {
  if (typeof obj !== 'object') {
    throw obj + ' is not an object' ;
  }

  var sources = slice.call(arguments, 1);

  each.call(sources, function (source) {
    if (source) {
      for (var prop in source) {
        if (typeof source[prop] === 'object' && obj[prop]) {
          extend$1.call(obj, obj[prop], source[prop]);
        } else {
          obj[prop] = source[prop];
        }
      }
    }
  });

  return obj;
}

function tryFilter(filter, doc, req) {
  try {
    return !filter(doc, req);
  } catch (err) {
    var msg = 'Filter function threw: ' + err.toString();
    return pouchdbErrors.createError(pouchdbErrors.BAD_REQUEST, msg);
  }
}

function filterChange(opts) {
  var req = {};
  var hasFilter = opts.filter && typeof opts.filter === 'function';
  req.query = opts.query_params;

  return function filter(change) {
    if (!change.doc) {
      // CSG sends events on the changes feed that don't have documents,
      // this hack makes a whole lot of existing code robust.
      change.doc = {};
    }

    var filterReturn = hasFilter && tryFilter(opts.filter, change.doc, req);

    if (typeof filterReturn === 'object') {
      return filterReturn;
    }

    if (filterReturn) {
      return false;
    }

    if (!opts.include_docs) {
      delete change.doc;
    } else if (!opts.attachments) {
      for (var att in change.doc._attachments) {
        /* istanbul ignore else */
        if (change.doc._attachments.hasOwnProperty(att)) {
          change.doc._attachments[att].stub = true;
        }
      }
    }
    return true;
  };
}

function flatten(arrs) {
  var res = [];
  for (var i = 0, len = arrs.length; i < len; i++) {
    res = res.concat(arrs[i]);
  }
  return res;
}

// shim for Function.prototype.name,
// for browsers that don't support it like IE

/* istanbul ignore next */
function f() {}

var hasName = f.name;
var res;

// We dont run coverage in IE
/* istanbul ignore else */
if (hasName) {
  res = function (fun) {
    return fun.name;
  };
} else {
  res = function (fun) {
    return fun.toString().match(/^\s*function\s*(\S*)\s*\(/)[1];
  };
}

var functionName = res;

// Determine id an ID is valid
//   - invalid IDs begin with an underescore that does not begin '_design' or
//     '_local'
//   - any other string value is a valid id
// Returns the specific error object for each case
function invalidIdError(id) {
  var err;
  if (!id) {
    err = pouchdbErrors.createError(pouchdbErrors.MISSING_ID);
  } else if (typeof id !== 'string') {
    err = pouchdbErrors.createError(pouchdbErrors.INVALID_ID);
  } else if (/^_/.test(id) && !(/^_(design|local)/).test(id)) {
    err = pouchdbErrors.createError(pouchdbErrors.RESERVED_ID);
  }
  if (err) {
    throw err;
  }
}

function isCordova() {
  return (typeof cordova !== "undefined" ||
  typeof PhoneGap !== "undefined" ||
  typeof phonegap !== "undefined");
}

function listenerCount(ee, type) {
  return 'listenerCount' in ee ? ee.listenerCount(type) :
                                 events.EventEmitter.listenerCount(ee, type);
}

function parseDesignDocFunctionName(s) {
  if (!s) {
    return null;
  }
  var parts = s.split('/');
  if (parts.length === 2) {
    return parts;
  }
  if (parts.length === 1) {
    return [s, s];
  }
  return null;
}

function normalizeDesignDocFunctionName(s) {
  var normalized = parseDesignDocFunctionName(s);
  return normalized ? normalized.join('/') : null;
}

// originally parseUri 1.2.2, now patched by us
// (c) Steven Levithan <stevenlevithan.com>
// MIT License
var keys = ["source", "protocol", "authority", "userInfo", "user", "password",
    "host", "port", "relative", "path", "directory", "file", "query", "anchor"];
var qName ="queryKey";
var qParser = /(?:^|&)([^&=]*)=?([^&]*)/g;

// use the "loose" parser
/* jshint maxlen: false */
var parser = /^(?:(?![^:@]+:[^:@\/]*@)([^:\/?#.]+):)?(?:\/\/)?((?:(([^:@]*)(?::([^:@]*))?)?@)?([^:\/?#]*)(?::(\d*))?)(((\/(?:[^?#](?![^?#\/]*\.[^?#\/.]+(?:[?#]|$)))*\/?)?([^?#\/]*))(?:\?([^#]*))?(?:#(.*))?)/;

function parseUri(str) {
  var m = parser.exec(str);
  var uri = {};
  var i = 14;

  while (i--) {
    var key = keys[i];
    var value = m[i] || "";
    var encoded = ['user', 'password'].indexOf(key) !== -1;
    uri[key] = encoded ? decodeURIComponent(value) : value;
  }

  uri[qName] = {};
  uri[keys[12]].replace(qParser, function ($0, $1, $2) {
    if ($1) {
      uri[qName][$1] = $2;
    }
  });

  return uri;
}

// this is essentially the "update sugar" function from daleharvey/pouchdb#1388
// the diffFun tells us what delta to apply to the doc.  it either returns
// the doc, or false if it doesn't need to do an update after all
function upsert(db, docId, diffFun) {
  return new Promise(function (fulfill, reject) {
    db.get(docId, function (err, doc) {
      if (err) {
        /* istanbul ignore next */
        if (err.status !== 404) {
          return reject(err);
        }
        doc = {};
      }

      // the user might change the _rev, so save it for posterity
      var docRev = doc._rev;
      var newDoc = diffFun(doc);

      if (!newDoc) {
        // if the diffFun returns falsy, we short-circuit as
        // an optimization
        return fulfill({updated: false, rev: docRev});
      }

      // users aren't allowed to modify these values,
      // so reset them here
      newDoc._id = docId;
      newDoc._rev = docRev;
      fulfill(tryAndPut(db, newDoc, diffFun));
    });
  });
}

function tryAndPut(db, doc, diffFun) {
  return db.put(doc).then(function (res) {
    return {
      updated: true,
      rev: res.rev
    };
  }, function (err) {
    /* istanbul ignore next */
    if (err.status !== 409) {
      throw err;
    }
    return upsert(db, doc._id, diffFun);
  });
}

// BEGIN Math.uuid.js

/*!
Math.uuid.js (v1.4)
http://www.broofa.com
mailto:robert@broofa.com

Copyright (c) 2010 Robert Kieffer
Dual licensed under the MIT and GPL licenses.
*/

/*
 * Generate a random uuid.
 *
 * USAGE: Math.uuid(length, radix)
 *   length - the desired number of characters
 *   radix  - the number of allowable values for each character.
 *
 * EXAMPLES:
 *   // No arguments  - returns RFC4122, version 4 ID
 *   >>> Math.uuid()
 *   "92329D39-6F5C-4520-ABFC-AAB64544E172"
 *
 *   // One argument - returns ID of the specified length
 *   >>> Math.uuid(15)     // 15 character ID (default base=62)
 *   "VcydxgltxrVZSTV"
 *
 *   // Two arguments - returns ID of the specified length, and radix. 
 *   // (Radix must be <= 62)
 *   >>> Math.uuid(8, 2)  // 8 character ID (base=2)
 *   "01001010"
 *   >>> Math.uuid(8, 10) // 8 character ID (base=10)
 *   "47473046"
 *   >>> Math.uuid(8, 16) // 8 character ID (base=16)
 *   "098F4D35"
 */
var chars = (
  '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ' +
  'abcdefghijklmnopqrstuvwxyz'
).split('');
function getValue(radix) {
  return 0 | Math.random() * radix;
}
function uuid(len, radix) {
  radix = radix || chars.length;
  var out = '';
  var i = -1;

  if (len) {
    // Compact form
    while (++i < len) {
      out += chars[getValue(radix)];
    }
    return out;
  }
    // rfc4122, version 4 form
    // Fill in random data.  At i==19 set the high bits of clock sequence as
    // per rfc4122, sec. 4.1.5
  while (++i < 36) {
    switch (i) {
      case 8:
      case 13:
      case 18:
      case 23:
        out += '-';
        break;
      case 19:
        out += chars[(getValue(16) & 0x3) | 0x8];
        break;
      default:
        out += chars[getValue(16)];
    }
  }

  return out;
}

exports.adapterFun = adapterFun;
exports.bulkGetShim = bulkGet;
exports.changesHandler = Changes;
exports.clone = clone;
exports.defaultBackOff = defaultBackOff;
exports.explainError = explainError;
exports.extend = extend;
exports.jsExtend = extend$1;
exports.filterChange = filterChange;
exports.flatten = flatten;
exports.functionName = functionName;
exports.guardedConsole = guardedConsole;
exports.hasLocalStorage = hasLocalStorage;
exports.invalidIdError = invalidIdError;
exports.isChromeApp = isChromeApp;
exports.isCordova = isCordova;
exports.listenerCount = listenerCount;
exports.normalizeDdocFunctionName = normalizeDesignDocFunctionName;
exports.once = once;
exports.parseDdocFunctionName = parseDesignDocFunctionName;
exports.parseUri = parseUri;
exports.pick = pick;
exports.toPromise = toPromise;
exports.upsert = upsert;
exports.uuid = uuid;
}).call(this,require('_process'))
},{"_process":113,"argsarray":5,"debug":8,"events":107,"inherits":28,"pouchdb-errors":64,"pouchdb-promise":68}],70:[function(require,module,exports){
(function (process){
'use strict';

if (!process.version ||
    process.version.indexOf('v0.') === 0 ||
    process.version.indexOf('v1.') === 0 && process.version.indexOf('v1.8.') !== 0) {
  module.exports = nextTick;
} else {
  module.exports = process.nextTick;
}

function nextTick(fn, arg1, arg2, arg3) {
  if (typeof fn !== 'function') {
    throw new TypeError('"callback" argument must be a function');
  }
  var len = arguments.length;
  var args, i;
  switch (len) {
  case 0:
  case 1:
    return process.nextTick(fn);
  case 2:
    return process.nextTick(function afterTickOne() {
      fn.call(null, arg1);
    });
  case 3:
    return process.nextTick(function afterTickTwo() {
      fn.call(null, arg1, arg2);
    });
  case 4:
    return process.nextTick(function afterTickThree() {
      fn.call(null, arg1, arg2, arg3);
    });
  default:
    args = new Array(len - 1);
    i = 0;
    while (i < args.length) {
      args[i++] = arguments[i];
    }
    return process.nextTick(function afterTick() {
      fn.apply(null, args);
    });
  }
}

}).call(this,require('_process'))
},{"_process":113}],71:[function(require,module,exports){
arguments[4][21][0].apply(exports,arguments)
},{"dup":21}],72:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// a duplex stream is just a stream that is both readable and writable.
// Since JS doesn't have multiple prototypal inheritance, this class
// prototypally inherits from Readable, and then parasitically from
// Writable.

module.exports = Duplex;

/*<replacement>*/
var objectKeys = Object.keys || function (obj) {
  var keys = [];
  for (var key in obj) keys.push(key);
  return keys;
}
/*</replacement>*/


/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var Readable = require('./_stream_readable');
var Writable = require('./_stream_writable');

util.inherits(Duplex, Readable);

forEach(objectKeys(Writable.prototype), function(method) {
  if (!Duplex.prototype[method])
    Duplex.prototype[method] = Writable.prototype[method];
});

function Duplex(options) {
  if (!(this instanceof Duplex))
    return new Duplex(options);

  Readable.call(this, options);
  Writable.call(this, options);

  if (options && options.readable === false)
    this.readable = false;

  if (options && options.writable === false)
    this.writable = false;

  this.allowHalfOpen = true;
  if (options && options.allowHalfOpen === false)
    this.allowHalfOpen = false;

  this.once('end', onend);
}

// the no-half-open enforcer
function onend() {
  // if we allow half-open state, or if the writable side ended,
  // then we're ok.
  if (this.allowHalfOpen || this._writableState.ended)
    return;

  // no more data can be written.
  // But allow more writes to happen in this tick.
  process.nextTick(this.end.bind(this));
}

function forEach (xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}

}).call(this,require('_process'))
},{"./_stream_readable":74,"./_stream_writable":76,"_process":113,"core-util-is":6,"inherits":28}],73:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// a passthrough stream.
// basically just the most minimal sort of Transform stream.
// Every written chunk gets output as-is.

module.exports = PassThrough;

var Transform = require('./_stream_transform');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

util.inherits(PassThrough, Transform);

function PassThrough(options) {
  if (!(this instanceof PassThrough))
    return new PassThrough(options);

  Transform.call(this, options);
}

PassThrough.prototype._transform = function(chunk, encoding, cb) {
  cb(null, chunk);
};

},{"./_stream_transform":75,"core-util-is":6,"inherits":28}],74:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

module.exports = Readable;

/*<replacement>*/
var isArray = require('isarray');
/*</replacement>*/


/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Readable.ReadableState = ReadableState;

var EE = require('events').EventEmitter;

/*<replacement>*/
if (!EE.listenerCount) EE.listenerCount = function(emitter, type) {
  return emitter.listeners(type).length;
};
/*</replacement>*/

var Stream = require('stream');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var StringDecoder;


/*<replacement>*/
var debug = require('util');
if (debug && debug.debuglog) {
  debug = debug.debuglog('stream');
} else {
  debug = function () {};
}
/*</replacement>*/


util.inherits(Readable, Stream);

function ReadableState(options, stream) {
  var Duplex = require('./_stream_duplex');

  options = options || {};

  // the point at which it stops calling _read() to fill the buffer
  // Note: 0 is a valid value, means "don't call _read preemptively ever"
  var hwm = options.highWaterMark;
  var defaultHwm = options.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;

  // cast to ints.
  this.highWaterMark = ~~this.highWaterMark;

  this.buffer = [];
  this.length = 0;
  this.pipes = null;
  this.pipesCount = 0;
  this.flowing = null;
  this.ended = false;
  this.endEmitted = false;
  this.reading = false;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // whenever we return null, then we set a flag to say
  // that we're awaiting a 'readable' event emission.
  this.needReadable = false;
  this.emittedReadable = false;
  this.readableListening = false;


  // object stream flag. Used to make read(n) ignore n and to
  // make all the buffer merging and length checks go away
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex)
    this.objectMode = this.objectMode || !!options.readableObjectMode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // when piping, we only care about 'readable' events that happen
  // after read()ing all the bytes and not getting any pushback.
  this.ranOut = false;

  // the number of writers that are awaiting a drain event in .pipe()s
  this.awaitDrain = 0;

  // if true, a maybeReadMore has been scheduled
  this.readingMore = false;

  this.decoder = null;
  this.encoding = null;
  if (options.encoding) {
    if (!StringDecoder)
      StringDecoder = require('string_decoder/').StringDecoder;
    this.decoder = new StringDecoder(options.encoding);
    this.encoding = options.encoding;
  }
}

function Readable(options) {
  var Duplex = require('./_stream_duplex');

  if (!(this instanceof Readable))
    return new Readable(options);

  this._readableState = new ReadableState(options, this);

  // legacy
  this.readable = true;

  Stream.call(this);
}

// Manually shove something into the read() buffer.
// This returns true if the highWaterMark has not been hit yet,
// similar to how Writable.write() returns true if you should
// write() some more.
Readable.prototype.push = function(chunk, encoding) {
  var state = this._readableState;

  if (util.isString(chunk) && !state.objectMode) {
    encoding = encoding || state.defaultEncoding;
    if (encoding !== state.encoding) {
      chunk = new Buffer(chunk, encoding);
      encoding = '';
    }
  }

  return readableAddChunk(this, state, chunk, encoding, false);
};

// Unshift should *always* be something directly out of read()
Readable.prototype.unshift = function(chunk) {
  var state = this._readableState;
  return readableAddChunk(this, state, chunk, '', true);
};

function readableAddChunk(stream, state, chunk, encoding, addToFront) {
  var er = chunkInvalid(state, chunk);
  if (er) {
    stream.emit('error', er);
  } else if (util.isNullOrUndefined(chunk)) {
    state.reading = false;
    if (!state.ended)
      onEofChunk(stream, state);
  } else if (state.objectMode || chunk && chunk.length > 0) {
    if (state.ended && !addToFront) {
      var e = new Error('stream.push() after EOF');
      stream.emit('error', e);
    } else if (state.endEmitted && addToFront) {
      var e = new Error('stream.unshift() after end event');
      stream.emit('error', e);
    } else {
      if (state.decoder && !addToFront && !encoding)
        chunk = state.decoder.write(chunk);

      if (!addToFront)
        state.reading = false;

      // if we want the data now, just emit it.
      if (state.flowing && state.length === 0 && !state.sync) {
        stream.emit('data', chunk);
        stream.read(0);
      } else {
        // update the buffer info.
        state.length += state.objectMode ? 1 : chunk.length;
        if (addToFront)
          state.buffer.unshift(chunk);
        else
          state.buffer.push(chunk);

        if (state.needReadable)
          emitReadable(stream);
      }

      maybeReadMore(stream, state);
    }
  } else if (!addToFront) {
    state.reading = false;
  }

  return needMoreData(state);
}



// if it's past the high water mark, we can push in some more.
// Also, if we have no data yet, we can stand some
// more bytes.  This is to work around cases where hwm=0,
// such as the repl.  Also, if the push() triggered a
// readable event, and the user called read(largeNumber) such that
// needReadable was set, then we ought to push more, so that another
// 'readable' event will be triggered.
function needMoreData(state) {
  return !state.ended &&
         (state.needReadable ||
          state.length < state.highWaterMark ||
          state.length === 0);
}

// backwards compatibility.
Readable.prototype.setEncoding = function(enc) {
  if (!StringDecoder)
    StringDecoder = require('string_decoder/').StringDecoder;
  this._readableState.decoder = new StringDecoder(enc);
  this._readableState.encoding = enc;
  return this;
};

// Don't raise the hwm > 128MB
var MAX_HWM = 0x800000;
function roundUpToNextPowerOf2(n) {
  if (n >= MAX_HWM) {
    n = MAX_HWM;
  } else {
    // Get the next highest power of 2
    n--;
    for (var p = 1; p < 32; p <<= 1) n |= n >> p;
    n++;
  }
  return n;
}

function howMuchToRead(n, state) {
  if (state.length === 0 && state.ended)
    return 0;

  if (state.objectMode)
    return n === 0 ? 0 : 1;

  if (isNaN(n) || util.isNull(n)) {
    // only flow one buffer at a time
    if (state.flowing && state.buffer.length)
      return state.buffer[0].length;
    else
      return state.length;
  }

  if (n <= 0)
    return 0;

  // If we're asking for more than the target buffer level,
  // then raise the water mark.  Bump up to the next highest
  // power of 2, to prevent increasing it excessively in tiny
  // amounts.
  if (n > state.highWaterMark)
    state.highWaterMark = roundUpToNextPowerOf2(n);

  // don't have that much.  return null, unless we've ended.
  if (n > state.length) {
    if (!state.ended) {
      state.needReadable = true;
      return 0;
    } else
      return state.length;
  }

  return n;
}

// you can override either this method, or the async _read(n) below.
Readable.prototype.read = function(n) {
  debug('read', n);
  var state = this._readableState;
  var nOrig = n;

  if (!util.isNumber(n) || n > 0)
    state.emittedReadable = false;

  // if we're doing read(0) to trigger a readable event, but we
  // already have a bunch of data in the buffer, then just trigger
  // the 'readable' event and move on.
  if (n === 0 &&
      state.needReadable &&
      (state.length >= state.highWaterMark || state.ended)) {
    debug('read: emitReadable', state.length, state.ended);
    if (state.length === 0 && state.ended)
      endReadable(this);
    else
      emitReadable(this);
    return null;
  }

  n = howMuchToRead(n, state);

  // if we've ended, and we're now clear, then finish it up.
  if (n === 0 && state.ended) {
    if (state.length === 0)
      endReadable(this);
    return null;
  }

  // All the actual chunk generation logic needs to be
  // *below* the call to _read.  The reason is that in certain
  // synthetic stream cases, such as passthrough streams, _read
  // may be a completely synchronous operation which may change
  // the state of the read buffer, providing enough data when
  // before there was *not* enough.
  //
  // So, the steps are:
  // 1. Figure out what the state of things will be after we do
  // a read from the buffer.
  //
  // 2. If that resulting state will trigger a _read, then call _read.
  // Note that this may be asynchronous, or synchronous.  Yes, it is
  // deeply ugly to write APIs this way, but that still doesn't mean
  // that the Readable class should behave improperly, as streams are
  // designed to be sync/async agnostic.
  // Take note if the _read call is sync or async (ie, if the read call
  // has returned yet), so that we know whether or not it's safe to emit
  // 'readable' etc.
  //
  // 3. Actually pull the requested chunks out of the buffer and return.

  // if we need a readable event, then we need to do some reading.
  var doRead = state.needReadable;
  debug('need readable', doRead);

  // if we currently have less than the highWaterMark, then also read some
  if (state.length === 0 || state.length - n < state.highWaterMark) {
    doRead = true;
    debug('length less than watermark', doRead);
  }

  // however, if we've ended, then there's no point, and if we're already
  // reading, then it's unnecessary.
  if (state.ended || state.reading) {
    doRead = false;
    debug('reading or ended', doRead);
  }

  if (doRead) {
    debug('do read');
    state.reading = true;
    state.sync = true;
    // if the length is currently zero, then we *need* a readable event.
    if (state.length === 0)
      state.needReadable = true;
    // call internal read method
    this._read(state.highWaterMark);
    state.sync = false;
  }

  // If _read pushed data synchronously, then `reading` will be false,
  // and we need to re-evaluate how much data we can return to the user.
  if (doRead && !state.reading)
    n = howMuchToRead(nOrig, state);

  var ret;
  if (n > 0)
    ret = fromList(n, state);
  else
    ret = null;

  if (util.isNull(ret)) {
    state.needReadable = true;
    n = 0;
  }

  state.length -= n;

  // If we have nothing in the buffer, then we want to know
  // as soon as we *do* get something into the buffer.
  if (state.length === 0 && !state.ended)
    state.needReadable = true;

  // If we tried to read() past the EOF, then emit end on the next tick.
  if (nOrig !== n && state.ended && state.length === 0)
    endReadable(this);

  if (!util.isNull(ret))
    this.emit('data', ret);

  return ret;
};

function chunkInvalid(state, chunk) {
  var er = null;
  if (!util.isBuffer(chunk) &&
      !util.isString(chunk) &&
      !util.isNullOrUndefined(chunk) &&
      !state.objectMode) {
    er = new TypeError('Invalid non-string/buffer chunk');
  }
  return er;
}


function onEofChunk(stream, state) {
  if (state.decoder && !state.ended) {
    var chunk = state.decoder.end();
    if (chunk && chunk.length) {
      state.buffer.push(chunk);
      state.length += state.objectMode ? 1 : chunk.length;
    }
  }
  state.ended = true;

  // emit 'readable' now to make sure it gets picked up.
  emitReadable(stream);
}

// Don't emit readable right away in sync mode, because this can trigger
// another read() call => stack overflow.  This way, it might trigger
// a nextTick recursion warning, but that's not so bad.
function emitReadable(stream) {
  var state = stream._readableState;
  state.needReadable = false;
  if (!state.emittedReadable) {
    debug('emitReadable', state.flowing);
    state.emittedReadable = true;
    if (state.sync)
      process.nextTick(function() {
        emitReadable_(stream);
      });
    else
      emitReadable_(stream);
  }
}

function emitReadable_(stream) {
  debug('emit readable');
  stream.emit('readable');
  flow(stream);
}


// at this point, the user has presumably seen the 'readable' event,
// and called read() to consume some data.  that may have triggered
// in turn another _read(n) call, in which case reading = true if
// it's in progress.
// However, if we're not ended, or reading, and the length < hwm,
// then go ahead and try to read some more preemptively.
function maybeReadMore(stream, state) {
  if (!state.readingMore) {
    state.readingMore = true;
    process.nextTick(function() {
      maybeReadMore_(stream, state);
    });
  }
}

function maybeReadMore_(stream, state) {
  var len = state.length;
  while (!state.reading && !state.flowing && !state.ended &&
         state.length < state.highWaterMark) {
    debug('maybeReadMore read 0');
    stream.read(0);
    if (len === state.length)
      // didn't get any data, stop spinning.
      break;
    else
      len = state.length;
  }
  state.readingMore = false;
}

// abstract method.  to be overridden in specific implementation classes.
// call cb(er, data) where data is <= n in length.
// for virtual (non-string, non-buffer) streams, "length" is somewhat
// arbitrary, and perhaps not very meaningful.
Readable.prototype._read = function(n) {
  this.emit('error', new Error('not implemented'));
};

Readable.prototype.pipe = function(dest, pipeOpts) {
  var src = this;
  var state = this._readableState;

  switch (state.pipesCount) {
    case 0:
      state.pipes = dest;
      break;
    case 1:
      state.pipes = [state.pipes, dest];
      break;
    default:
      state.pipes.push(dest);
      break;
  }
  state.pipesCount += 1;
  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);

  var doEnd = (!pipeOpts || pipeOpts.end !== false) &&
              dest !== process.stdout &&
              dest !== process.stderr;

  var endFn = doEnd ? onend : cleanup;
  if (state.endEmitted)
    process.nextTick(endFn);
  else
    src.once('end', endFn);

  dest.on('unpipe', onunpipe);
  function onunpipe(readable) {
    debug('onunpipe');
    if (readable === src) {
      cleanup();
    }
  }

  function onend() {
    debug('onend');
    dest.end();
  }

  // when the dest drains, it reduces the awaitDrain counter
  // on the source.  This would be more elegant with a .once()
  // handler in flow(), but adding and removing repeatedly is
  // too slow.
  var ondrain = pipeOnDrain(src);
  dest.on('drain', ondrain);

  function cleanup() {
    debug('cleanup');
    // cleanup event handlers once the pipe is broken
    dest.removeListener('close', onclose);
    dest.removeListener('finish', onfinish);
    dest.removeListener('drain', ondrain);
    dest.removeListener('error', onerror);
    dest.removeListener('unpipe', onunpipe);
    src.removeListener('end', onend);
    src.removeListener('end', cleanup);
    src.removeListener('data', ondata);

    // if the reader is waiting for a drain event from this
    // specific writer, then it would cause it to never start
    // flowing again.
    // So, if this is awaiting a drain, then we just call it now.
    // If we don't know, then assume that we are waiting for one.
    if (state.awaitDrain &&
        (!dest._writableState || dest._writableState.needDrain))
      ondrain();
  }

  src.on('data', ondata);
  function ondata(chunk) {
    debug('ondata');
    var ret = dest.write(chunk);
    if (false === ret) {
      debug('false write response, pause',
            src._readableState.awaitDrain);
      src._readableState.awaitDrain++;
      src.pause();
    }
  }

  // if the dest has an error, then stop piping into it.
  // however, don't suppress the throwing behavior for this.
  function onerror(er) {
    debug('onerror', er);
    unpipe();
    dest.removeListener('error', onerror);
    if (EE.listenerCount(dest, 'error') === 0)
      dest.emit('error', er);
  }
  // This is a brutally ugly hack to make sure that our error handler
  // is attached before any userland ones.  NEVER DO THIS.
  if (!dest._events || !dest._events.error)
    dest.on('error', onerror);
  else if (isArray(dest._events.error))
    dest._events.error.unshift(onerror);
  else
    dest._events.error = [onerror, dest._events.error];



  // Both close and finish should trigger unpipe, but only once.
  function onclose() {
    dest.removeListener('finish', onfinish);
    unpipe();
  }
  dest.once('close', onclose);
  function onfinish() {
    debug('onfinish');
    dest.removeListener('close', onclose);
    unpipe();
  }
  dest.once('finish', onfinish);

  function unpipe() {
    debug('unpipe');
    src.unpipe(dest);
  }

  // tell the dest that it's being piped to
  dest.emit('pipe', src);

  // start the flow if it hasn't been started already.
  if (!state.flowing) {
    debug('pipe resume');
    src.resume();
  }

  return dest;
};

function pipeOnDrain(src) {
  return function() {
    var state = src._readableState;
    debug('pipeOnDrain', state.awaitDrain);
    if (state.awaitDrain)
      state.awaitDrain--;
    if (state.awaitDrain === 0 && EE.listenerCount(src, 'data')) {
      state.flowing = true;
      flow(src);
    }
  };
}


Readable.prototype.unpipe = function(dest) {
  var state = this._readableState;

  // if we're not piping anywhere, then do nothing.
  if (state.pipesCount === 0)
    return this;

  // just one destination.  most common case.
  if (state.pipesCount === 1) {
    // passed in one, but it's not the right one.
    if (dest && dest !== state.pipes)
      return this;

    if (!dest)
      dest = state.pipes;

    // got a match.
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;
    if (dest)
      dest.emit('unpipe', this);
    return this;
  }

  // slow case. multiple pipe destinations.

  if (!dest) {
    // remove all.
    var dests = state.pipes;
    var len = state.pipesCount;
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;

    for (var i = 0; i < len; i++)
      dests[i].emit('unpipe', this);
    return this;
  }

  // try to find the right one.
  var i = indexOf(state.pipes, dest);
  if (i === -1)
    return this;

  state.pipes.splice(i, 1);
  state.pipesCount -= 1;
  if (state.pipesCount === 1)
    state.pipes = state.pipes[0];

  dest.emit('unpipe', this);

  return this;
};

// set up data events if they are asked for
// Ensure readable listeners eventually get something
Readable.prototype.on = function(ev, fn) {
  var res = Stream.prototype.on.call(this, ev, fn);

  // If listening to data, and it has not explicitly been paused,
  // then call resume to start the flow of data on the next tick.
  if (ev === 'data' && false !== this._readableState.flowing) {
    this.resume();
  }

  if (ev === 'readable' && this.readable) {
    var state = this._readableState;
    if (!state.readableListening) {
      state.readableListening = true;
      state.emittedReadable = false;
      state.needReadable = true;
      if (!state.reading) {
        var self = this;
        process.nextTick(function() {
          debug('readable nexttick read 0');
          self.read(0);
        });
      } else if (state.length) {
        emitReadable(this, state);
      }
    }
  }

  return res;
};
Readable.prototype.addListener = Readable.prototype.on;

// pause() and resume() are remnants of the legacy readable stream API
// If the user uses them, then switch into old mode.
Readable.prototype.resume = function() {
  var state = this._readableState;
  if (!state.flowing) {
    debug('resume');
    state.flowing = true;
    if (!state.reading) {
      debug('resume read 0');
      this.read(0);
    }
    resume(this, state);
  }
  return this;
};

function resume(stream, state) {
  if (!state.resumeScheduled) {
    state.resumeScheduled = true;
    process.nextTick(function() {
      resume_(stream, state);
    });
  }
}

function resume_(stream, state) {
  state.resumeScheduled = false;
  stream.emit('resume');
  flow(stream);
  if (state.flowing && !state.reading)
    stream.read(0);
}

Readable.prototype.pause = function() {
  debug('call pause flowing=%j', this._readableState.flowing);
  if (false !== this._readableState.flowing) {
    debug('pause');
    this._readableState.flowing = false;
    this.emit('pause');
  }
  return this;
};

function flow(stream) {
  var state = stream._readableState;
  debug('flow', state.flowing);
  if (state.flowing) {
    do {
      var chunk = stream.read();
    } while (null !== chunk && state.flowing);
  }
}

// wrap an old-style stream as the async data source.
// This is *not* part of the readable stream interface.
// It is an ugly unfortunate mess of history.
Readable.prototype.wrap = function(stream) {
  var state = this._readableState;
  var paused = false;

  var self = this;
  stream.on('end', function() {
    debug('wrapped end');
    if (state.decoder && !state.ended) {
      var chunk = state.decoder.end();
      if (chunk && chunk.length)
        self.push(chunk);
    }

    self.push(null);
  });

  stream.on('data', function(chunk) {
    debug('wrapped data');
    if (state.decoder)
      chunk = state.decoder.write(chunk);
    if (!chunk || !state.objectMode && !chunk.length)
      return;

    var ret = self.push(chunk);
    if (!ret) {
      paused = true;
      stream.pause();
    }
  });

  // proxy all the other methods.
  // important when wrapping filters and duplexes.
  for (var i in stream) {
    if (util.isFunction(stream[i]) && util.isUndefined(this[i])) {
      this[i] = function(method) { return function() {
        return stream[method].apply(stream, arguments);
      }}(i);
    }
  }

  // proxy certain important events.
  var events = ['error', 'close', 'destroy', 'pause', 'resume'];
  forEach(events, function(ev) {
    stream.on(ev, self.emit.bind(self, ev));
  });

  // when we try to consume some more bytes, simply unpause the
  // underlying stream.
  self._read = function(n) {
    debug('wrapped _read', n);
    if (paused) {
      paused = false;
      stream.resume();
    }
  };

  return self;
};



// exposed for testing purposes only.
Readable._fromList = fromList;

// Pluck off n bytes from an array of buffers.
// Length is the combined lengths of all the buffers in the list.
function fromList(n, state) {
  var list = state.buffer;
  var length = state.length;
  var stringMode = !!state.decoder;
  var objectMode = !!state.objectMode;
  var ret;

  // nothing in the list, definitely empty.
  if (list.length === 0)
    return null;

  if (length === 0)
    ret = null;
  else if (objectMode)
    ret = list.shift();
  else if (!n || n >= length) {
    // read it all, truncate the array.
    if (stringMode)
      ret = list.join('');
    else
      ret = Buffer.concat(list, length);
    list.length = 0;
  } else {
    // read just some of it.
    if (n < list[0].length) {
      // just take a part of the first list item.
      // slice is the same for buffers and strings.
      var buf = list[0];
      ret = buf.slice(0, n);
      list[0] = buf.slice(n);
    } else if (n === list[0].length) {
      // first list is a perfect match
      ret = list.shift();
    } else {
      // complex case.
      // we have enough to cover it, but it spans past the first buffer.
      if (stringMode)
        ret = '';
      else
        ret = new Buffer(n);

      var c = 0;
      for (var i = 0, l = list.length; i < l && c < n; i++) {
        var buf = list[0];
        var cpy = Math.min(n - c, buf.length);

        if (stringMode)
          ret += buf.slice(0, cpy);
        else
          buf.copy(ret, c, 0, cpy);

        if (cpy < buf.length)
          list[0] = buf.slice(cpy);
        else
          list.shift();

        c += cpy;
      }
    }
  }

  return ret;
}

function endReadable(stream) {
  var state = stream._readableState;

  // If we get here before consuming all the bytes, then that is a
  // bug in node.  Should never happen.
  if (state.length > 0)
    throw new Error('endReadable called on non-empty stream');

  if (!state.endEmitted) {
    state.ended = true;
    process.nextTick(function() {
      // Check that we didn't get one last unshift.
      if (!state.endEmitted && state.length === 0) {
        state.endEmitted = true;
        stream.readable = false;
        stream.emit('end');
      }
    });
  }
}

function forEach (xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}

function indexOf (xs, x) {
  for (var i = 0, l = xs.length; i < l; i++) {
    if (xs[i] === x) return i;
  }
  return -1;
}

}).call(this,require('_process'))
},{"./_stream_duplex":72,"_process":113,"buffer":105,"core-util-is":6,"events":107,"inherits":28,"isarray":29,"stream":125,"string_decoder/":80,"util":103}],75:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.


// a transform stream is a readable/writable stream where you do
// something with the data.  Sometimes it's called a "filter",
// but that's not a great name for it, since that implies a thing where
// some bits pass through, and others are simply ignored.  (That would
// be a valid example of a transform, of course.)
//
// While the output is causally related to the input, it's not a
// necessarily symmetric or synchronous transformation.  For example,
// a zlib stream might take multiple plain-text writes(), and then
// emit a single compressed chunk some time in the future.
//
// Here's how this works:
//
// The Transform stream has all the aspects of the readable and writable
// stream classes.  When you write(chunk), that calls _write(chunk,cb)
// internally, and returns false if there's a lot of pending writes
// buffered up.  When you call read(), that calls _read(n) until
// there's enough pending readable data buffered up.
//
// In a transform stream, the written data is placed in a buffer.  When
// _read(n) is called, it transforms the queued up data, calling the
// buffered _write cb's as it consumes chunks.  If consuming a single
// written chunk would result in multiple output chunks, then the first
// outputted bit calls the readcb, and subsequent chunks just go into
// the read buffer, and will cause it to emit 'readable' if necessary.
//
// This way, back-pressure is actually determined by the reading side,
// since _read has to be called to start processing a new chunk.  However,
// a pathological inflate type of transform can cause excessive buffering
// here.  For example, imagine a stream where every byte of input is
// interpreted as an integer from 0-255, and then results in that many
// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
// 1kb of data being output.  In this case, you could write a very small
// amount of input, and end up with a very large amount of output.  In
// such a pathological inflating mechanism, there'd be no way to tell
// the system to stop doing the transform.  A single 4MB write could
// cause the system to run out of memory.
//
// However, even in such a pathological case, only a single written chunk
// would be consumed, and then the rest would wait (un-transformed) until
// the results of the previous transformed chunk were consumed.

module.exports = Transform;

var Duplex = require('./_stream_duplex');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

util.inherits(Transform, Duplex);


function TransformState(options, stream) {
  this.afterTransform = function(er, data) {
    return afterTransform(stream, er, data);
  };

  this.needTransform = false;
  this.transforming = false;
  this.writecb = null;
  this.writechunk = null;
}

function afterTransform(stream, er, data) {
  var ts = stream._transformState;
  ts.transforming = false;

  var cb = ts.writecb;

  if (!cb)
    return stream.emit('error', new Error('no writecb in Transform class'));

  ts.writechunk = null;
  ts.writecb = null;

  if (!util.isNullOrUndefined(data))
    stream.push(data);

  if (cb)
    cb(er);

  var rs = stream._readableState;
  rs.reading = false;
  if (rs.needReadable || rs.length < rs.highWaterMark) {
    stream._read(rs.highWaterMark);
  }
}


function Transform(options) {
  if (!(this instanceof Transform))
    return new Transform(options);

  Duplex.call(this, options);

  this._transformState = new TransformState(options, this);

  // when the writable side finishes, then flush out anything remaining.
  var stream = this;

  // start out asking for a readable event once data is transformed.
  this._readableState.needReadable = true;

  // we have implemented the _read method, and done the other things
  // that Readable wants before the first _read call, so unset the
  // sync guard flag.
  this._readableState.sync = false;

  this.once('prefinish', function() {
    if (util.isFunction(this._flush))
      this._flush(function(er) {
        done(stream, er);
      });
    else
      done(stream);
  });
}

Transform.prototype.push = function(chunk, encoding) {
  this._transformState.needTransform = false;
  return Duplex.prototype.push.call(this, chunk, encoding);
};

// This is the part where you do stuff!
// override this function in implementation classes.
// 'chunk' is an input chunk.
//
// Call `push(newChunk)` to pass along transformed output
// to the readable side.  You may call 'push' zero or more times.
//
// Call `cb(err)` when you are done with this chunk.  If you pass
// an error, then that'll put the hurt on the whole operation.  If you
// never call cb(), then you'll never get another chunk.
Transform.prototype._transform = function(chunk, encoding, cb) {
  throw new Error('not implemented');
};

Transform.prototype._write = function(chunk, encoding, cb) {
  var ts = this._transformState;
  ts.writecb = cb;
  ts.writechunk = chunk;
  ts.writeencoding = encoding;
  if (!ts.transforming) {
    var rs = this._readableState;
    if (ts.needTransform ||
        rs.needReadable ||
        rs.length < rs.highWaterMark)
      this._read(rs.highWaterMark);
  }
};

// Doesn't matter what the args are here.
// _transform does all the work.
// That we got here means that the readable side wants more data.
Transform.prototype._read = function(n) {
  var ts = this._transformState;

  if (!util.isNull(ts.writechunk) && ts.writecb && !ts.transforming) {
    ts.transforming = true;
    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
  } else {
    // mark that we need a transform, so that any data that comes in
    // will get processed, now that we've asked for it.
    ts.needTransform = true;
  }
};


function done(stream, er) {
  if (er)
    return stream.emit('error', er);

  // if there's nothing in the write buffer, then that means
  // that nothing more will ever be provided
  var ws = stream._writableState;
  var ts = stream._transformState;

  if (ws.length)
    throw new Error('calling transform done when ws.length != 0');

  if (ts.transforming)
    throw new Error('calling transform done when still transforming');

  return stream.push(null);
}

},{"./_stream_duplex":72,"core-util-is":6,"inherits":28}],76:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// A bit simpler than readable streams.
// Implement an async ._write(chunk, cb), and it'll handle all
// the drain event emission and buffering.

module.exports = Writable;

/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Writable.WritableState = WritableState;


/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var Stream = require('stream');

util.inherits(Writable, Stream);

function WriteReq(chunk, encoding, cb) {
  this.chunk = chunk;
  this.encoding = encoding;
  this.callback = cb;
}

function WritableState(options, stream) {
  var Duplex = require('./_stream_duplex');

  options = options || {};

  // the point at which write() starts returning false
  // Note: 0 is a valid value, means that we always return false if
  // the entire buffer is not flushed immediately on write()
  var hwm = options.highWaterMark;
  var defaultHwm = options.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;

  // object stream flag to indicate whether or not this stream
  // contains buffers or objects.
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex)
    this.objectMode = this.objectMode || !!options.writableObjectMode;

  // cast to ints.
  this.highWaterMark = ~~this.highWaterMark;

  this.needDrain = false;
  // at the start of calling end()
  this.ending = false;
  // when end() has been called, and returned
  this.ended = false;
  // when 'finish' is emitted
  this.finished = false;

  // should we decode strings into buffers before passing to _write?
  // this is here so that some node-core streams can optimize string
  // handling at a lower level.
  var noDecode = options.decodeStrings === false;
  this.decodeStrings = !noDecode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // not an actual buffer we keep track of, but a measurement
  // of how much we're waiting to get pushed to some underlying
  // socket or file.
  this.length = 0;

  // a flag to see when we're in the middle of a write.
  this.writing = false;

  // when true all writes will be buffered until .uncork() call
  this.corked = 0;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // a flag to know if we're processing previously buffered items, which
  // may call the _write() callback in the same tick, so that we don't
  // end up in an overlapped onwrite situation.
  this.bufferProcessing = false;

  // the callback that's passed to _write(chunk,cb)
  this.onwrite = function(er) {
    onwrite(stream, er);
  };

  // the callback that the user supplies to write(chunk,encoding,cb)
  this.writecb = null;

  // the amount that is being written when _write is called.
  this.writelen = 0;

  this.buffer = [];

  // number of pending user-supplied write callbacks
  // this must be 0 before 'finish' can be emitted
  this.pendingcb = 0;

  // emit prefinish if the only thing we're waiting for is _write cbs
  // This is relevant for synchronous Transform streams
  this.prefinished = false;

  // True if the error was already emitted and should not be thrown again
  this.errorEmitted = false;
}

function Writable(options) {
  var Duplex = require('./_stream_duplex');

  // Writable ctor is applied to Duplexes, though they're not
  // instanceof Writable, they're instanceof Readable.
  if (!(this instanceof Writable) && !(this instanceof Duplex))
    return new Writable(options);

  this._writableState = new WritableState(options, this);

  // legacy.
  this.writable = true;

  Stream.call(this);
}

// Otherwise people can pipe Writable streams, which is just wrong.
Writable.prototype.pipe = function() {
  this.emit('error', new Error('Cannot pipe. Not readable.'));
};


function writeAfterEnd(stream, state, cb) {
  var er = new Error('write after end');
  // TODO: defer error events consistently everywhere, not just the cb
  stream.emit('error', er);
  process.nextTick(function() {
    cb(er);
  });
}

// If we get something that is not a buffer, string, null, or undefined,
// and we're not in objectMode, then that's an error.
// Otherwise stream chunks are all considered to be of length=1, and the
// watermarks determine how many objects to keep in the buffer, rather than
// how many bytes or characters.
function validChunk(stream, state, chunk, cb) {
  var valid = true;
  if (!util.isBuffer(chunk) &&
      !util.isString(chunk) &&
      !util.isNullOrUndefined(chunk) &&
      !state.objectMode) {
    var er = new TypeError('Invalid non-string/buffer chunk');
    stream.emit('error', er);
    process.nextTick(function() {
      cb(er);
    });
    valid = false;
  }
  return valid;
}

Writable.prototype.write = function(chunk, encoding, cb) {
  var state = this._writableState;
  var ret = false;

  if (util.isFunction(encoding)) {
    cb = encoding;
    encoding = null;
  }

  if (util.isBuffer(chunk))
    encoding = 'buffer';
  else if (!encoding)
    encoding = state.defaultEncoding;

  if (!util.isFunction(cb))
    cb = function() {};

  if (state.ended)
    writeAfterEnd(this, state, cb);
  else if (validChunk(this, state, chunk, cb)) {
    state.pendingcb++;
    ret = writeOrBuffer(this, state, chunk, encoding, cb);
  }

  return ret;
};

Writable.prototype.cork = function() {
  var state = this._writableState;

  state.corked++;
};

Writable.prototype.uncork = function() {
  var state = this._writableState;

  if (state.corked) {
    state.corked--;

    if (!state.writing &&
        !state.corked &&
        !state.finished &&
        !state.bufferProcessing &&
        state.buffer.length)
      clearBuffer(this, state);
  }
};

function decodeChunk(state, chunk, encoding) {
  if (!state.objectMode &&
      state.decodeStrings !== false &&
      util.isString(chunk)) {
    chunk = new Buffer(chunk, encoding);
  }
  return chunk;
}

// if we're already writing something, then just put this
// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, cb) {
  chunk = decodeChunk(state, chunk, encoding);
  if (util.isBuffer(chunk))
    encoding = 'buffer';
  var len = state.objectMode ? 1 : chunk.length;

  state.length += len;

  var ret = state.length < state.highWaterMark;
  // we must ensure that previous needDrain will not be reset to false.
  if (!ret)
    state.needDrain = true;

  if (state.writing || state.corked)
    state.buffer.push(new WriteReq(chunk, encoding, cb));
  else
    doWrite(stream, state, false, len, chunk, encoding, cb);

  return ret;
}

function doWrite(stream, state, writev, len, chunk, encoding, cb) {
  state.writelen = len;
  state.writecb = cb;
  state.writing = true;
  state.sync = true;
  if (writev)
    stream._writev(chunk, state.onwrite);
  else
    stream._write(chunk, encoding, state.onwrite);
  state.sync = false;
}

function onwriteError(stream, state, sync, er, cb) {
  if (sync)
    process.nextTick(function() {
      state.pendingcb--;
      cb(er);
    });
  else {
    state.pendingcb--;
    cb(er);
  }

  stream._writableState.errorEmitted = true;
  stream.emit('error', er);
}

function onwriteStateUpdate(state) {
  state.writing = false;
  state.writecb = null;
  state.length -= state.writelen;
  state.writelen = 0;
}

function onwrite(stream, er) {
  var state = stream._writableState;
  var sync = state.sync;
  var cb = state.writecb;

  onwriteStateUpdate(state);

  if (er)
    onwriteError(stream, state, sync, er, cb);
  else {
    // Check if we're actually ready to finish, but don't emit yet
    var finished = needFinish(stream, state);

    if (!finished &&
        !state.corked &&
        !state.bufferProcessing &&
        state.buffer.length) {
      clearBuffer(stream, state);
    }

    if (sync) {
      process.nextTick(function() {
        afterWrite(stream, state, finished, cb);
      });
    } else {
      afterWrite(stream, state, finished, cb);
    }
  }
}

function afterWrite(stream, state, finished, cb) {
  if (!finished)
    onwriteDrain(stream, state);
  state.pendingcb--;
  cb();
  finishMaybe(stream, state);
}

// Must force callback to be called on nextTick, so that we don't
// emit 'drain' before the write() consumer gets the 'false' return
// value, and has a chance to attach a 'drain' listener.
function onwriteDrain(stream, state) {
  if (state.length === 0 && state.needDrain) {
    state.needDrain = false;
    stream.emit('drain');
  }
}


// if there's something in the buffer waiting, then process it
function clearBuffer(stream, state) {
  state.bufferProcessing = true;

  if (stream._writev && state.buffer.length > 1) {
    // Fast case, write everything using _writev()
    var cbs = [];
    for (var c = 0; c < state.buffer.length; c++)
      cbs.push(state.buffer[c].callback);

    // count the one we are adding, as well.
    // TODO(isaacs) clean this up
    state.pendingcb++;
    doWrite(stream, state, true, state.length, state.buffer, '', function(err) {
      for (var i = 0; i < cbs.length; i++) {
        state.pendingcb--;
        cbs[i](err);
      }
    });

    // Clear buffer
    state.buffer = [];
  } else {
    // Slow case, write chunks one-by-one
    for (var c = 0; c < state.buffer.length; c++) {
      var entry = state.buffer[c];
      var chunk = entry.chunk;
      var encoding = entry.encoding;
      var cb = entry.callback;
      var len = state.objectMode ? 1 : chunk.length;

      doWrite(stream, state, false, len, chunk, encoding, cb);

      // if we didn't call the onwrite immediately, then
      // it means that we need to wait until it does.
      // also, that means that the chunk and cb are currently
      // being processed, so move the buffer counter past them.
      if (state.writing) {
        c++;
        break;
      }
    }

    if (c < state.buffer.length)
      state.buffer = state.buffer.slice(c);
    else
      state.buffer.length = 0;
  }

  state.bufferProcessing = false;
}

Writable.prototype._write = function(chunk, encoding, cb) {
  cb(new Error('not implemented'));

};

Writable.prototype._writev = null;

Writable.prototype.end = function(chunk, encoding, cb) {
  var state = this._writableState;

  if (util.isFunction(chunk)) {
    cb = chunk;
    chunk = null;
    encoding = null;
  } else if (util.isFunction(encoding)) {
    cb = encoding;
    encoding = null;
  }

  if (!util.isNullOrUndefined(chunk))
    this.write(chunk, encoding);

  // .end() fully uncorks
  if (state.corked) {
    state.corked = 1;
    this.uncork();
  }

  // ignore unnecessary end() calls.
  if (!state.ending && !state.finished)
    endWritable(this, state, cb);
};


function needFinish(stream, state) {
  return (state.ending &&
          state.length === 0 &&
          !state.finished &&
          !state.writing);
}

function prefinish(stream, state) {
  if (!state.prefinished) {
    state.prefinished = true;
    stream.emit('prefinish');
  }
}

function finishMaybe(stream, state) {
  var need = needFinish(stream, state);
  if (need) {
    if (state.pendingcb === 0) {
      prefinish(stream, state);
      state.finished = true;
      stream.emit('finish');
    } else
      prefinish(stream, state);
  }
  return need;
}

function endWritable(stream, state, cb) {
  state.ending = true;
  finishMaybe(stream, state);
  if (cb) {
    if (state.finished)
      process.nextTick(cb);
    else
      stream.once('finish', cb);
  }
  state.ended = true;
}

}).call(this,require('_process'))
},{"./_stream_duplex":72,"_process":113,"buffer":105,"core-util-is":6,"inherits":28,"stream":125}],77:[function(require,module,exports){
(function (process){
exports = module.exports = require('./lib/_stream_readable.js');
exports.Stream = require('stream');
exports.Readable = exports;
exports.Writable = require('./lib/_stream_writable.js');
exports.Duplex = require('./lib/_stream_duplex.js');
exports.Transform = require('./lib/_stream_transform.js');
exports.PassThrough = require('./lib/_stream_passthrough.js');
if (!process.browser && process.env.READABLE_STREAM === 'disable') {
  module.exports = require('stream');
}

}).call(this,require('_process'))
},{"./lib/_stream_duplex.js":72,"./lib/_stream_passthrough.js":73,"./lib/_stream_readable.js":74,"./lib/_stream_transform.js":75,"./lib/_stream_writable.js":76,"_process":113,"stream":125}],78:[function(require,module,exports){
// Generated by CoffeeScript 1.9.2
(function() {
  var hasProp = {}.hasOwnProperty,
    slice = [].slice;

  module.exports = function(source, scope) {
    var key, keys, value, values;
    keys = [];
    values = [];
    for (key in scope) {
      if (!hasProp.call(scope, key)) continue;
      value = scope[key];
      if (key === 'this') {
        continue;
      }
      keys.push(key);
      values.push(value);
    }
    return Function.apply(null, slice.call(keys).concat([source])).apply(scope["this"], values);
  };

}).call(this);

},{}],79:[function(require,module,exports){
(function (factory) {
    if (typeof exports === 'object') {
        // Node/CommonJS
        module.exports = factory();
    } else if (typeof define === 'function' && define.amd) {
        // AMD
        define(factory);
    } else {
        // Browser globals (with support for web workers)
        var glob;

        try {
            glob = window;
        } catch (e) {
            glob = self;
        }

        glob.SparkMD5 = factory();
    }
}(function (undefined) {

    'use strict';

    /*
     * Fastest md5 implementation around (JKM md5).
     * Credits: Joseph Myers
     *
     * @see http://www.myersdaily.org/joseph/javascript/md5-text.html
     * @see http://jsperf.com/md5-shootout/7
     */

    /* this function is much faster,
      so if possible we use it. Some IEs
      are the only ones I know of that
      need the idiotic second function,
      generated by an if clause.  */
    var add32 = function (a, b) {
        return (a + b) & 0xFFFFFFFF;
    },
        hex_chr = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'];


    function cmn(q, a, b, x, s, t) {
        a = add32(add32(a, q), add32(x, t));
        return add32((a << s) | (a >>> (32 - s)), b);
    }

    function ff(a, b, c, d, x, s, t) {
        return cmn((b & c) | ((~b) & d), a, b, x, s, t);
    }

    function gg(a, b, c, d, x, s, t) {
        return cmn((b & d) | (c & (~d)), a, b, x, s, t);
    }

    function hh(a, b, c, d, x, s, t) {
        return cmn(b ^ c ^ d, a, b, x, s, t);
    }

    function ii(a, b, c, d, x, s, t) {
        return cmn(c ^ (b | (~d)), a, b, x, s, t);
    }

    function md5cycle(x, k) {
        var a = x[0],
            b = x[1],
            c = x[2],
            d = x[3];

        a = ff(a, b, c, d, k[0], 7, -680876936);
        d = ff(d, a, b, c, k[1], 12, -389564586);
        c = ff(c, d, a, b, k[2], 17, 606105819);
        b = ff(b, c, d, a, k[3], 22, -1044525330);
        a = ff(a, b, c, d, k[4], 7, -176418897);
        d = ff(d, a, b, c, k[5], 12, 1200080426);
        c = ff(c, d, a, b, k[6], 17, -1473231341);
        b = ff(b, c, d, a, k[7], 22, -45705983);
        a = ff(a, b, c, d, k[8], 7, 1770035416);
        d = ff(d, a, b, c, k[9], 12, -1958414417);
        c = ff(c, d, a, b, k[10], 17, -42063);
        b = ff(b, c, d, a, k[11], 22, -1990404162);
        a = ff(a, b, c, d, k[12], 7, 1804603682);
        d = ff(d, a, b, c, k[13], 12, -40341101);
        c = ff(c, d, a, b, k[14], 17, -1502002290);
        b = ff(b, c, d, a, k[15], 22, 1236535329);

        a = gg(a, b, c, d, k[1], 5, -165796510);
        d = gg(d, a, b, c, k[6], 9, -1069501632);
        c = gg(c, d, a, b, k[11], 14, 643717713);
        b = gg(b, c, d, a, k[0], 20, -373897302);
        a = gg(a, b, c, d, k[5], 5, -701558691);
        d = gg(d, a, b, c, k[10], 9, 38016083);
        c = gg(c, d, a, b, k[15], 14, -660478335);
        b = gg(b, c, d, a, k[4], 20, -405537848);
        a = gg(a, b, c, d, k[9], 5, 568446438);
        d = gg(d, a, b, c, k[14], 9, -1019803690);
        c = gg(c, d, a, b, k[3], 14, -187363961);
        b = gg(b, c, d, a, k[8], 20, 1163531501);
        a = gg(a, b, c, d, k[13], 5, -1444681467);
        d = gg(d, a, b, c, k[2], 9, -51403784);
        c = gg(c, d, a, b, k[7], 14, 1735328473);
        b = gg(b, c, d, a, k[12], 20, -1926607734);

        a = hh(a, b, c, d, k[5], 4, -378558);
        d = hh(d, a, b, c, k[8], 11, -2022574463);
        c = hh(c, d, a, b, k[11], 16, 1839030562);
        b = hh(b, c, d, a, k[14], 23, -35309556);
        a = hh(a, b, c, d, k[1], 4, -1530992060);
        d = hh(d, a, b, c, k[4], 11, 1272893353);
        c = hh(c, d, a, b, k[7], 16, -155497632);
        b = hh(b, c, d, a, k[10], 23, -1094730640);
        a = hh(a, b, c, d, k[13], 4, 681279174);
        d = hh(d, a, b, c, k[0], 11, -358537222);
        c = hh(c, d, a, b, k[3], 16, -722521979);
        b = hh(b, c, d, a, k[6], 23, 76029189);
        a = hh(a, b, c, d, k[9], 4, -640364487);
        d = hh(d, a, b, c, k[12], 11, -421815835);
        c = hh(c, d, a, b, k[15], 16, 530742520);
        b = hh(b, c, d, a, k[2], 23, -995338651);

        a = ii(a, b, c, d, k[0], 6, -198630844);
        d = ii(d, a, b, c, k[7], 10, 1126891415);
        c = ii(c, d, a, b, k[14], 15, -1416354905);
        b = ii(b, c, d, a, k[5], 21, -57434055);
        a = ii(a, b, c, d, k[12], 6, 1700485571);
        d = ii(d, a, b, c, k[3], 10, -1894986606);
        c = ii(c, d, a, b, k[10], 15, -1051523);
        b = ii(b, c, d, a, k[1], 21, -2054922799);
        a = ii(a, b, c, d, k[8], 6, 1873313359);
        d = ii(d, a, b, c, k[15], 10, -30611744);
        c = ii(c, d, a, b, k[6], 15, -1560198380);
        b = ii(b, c, d, a, k[13], 21, 1309151649);
        a = ii(a, b, c, d, k[4], 6, -145523070);
        d = ii(d, a, b, c, k[11], 10, -1120210379);
        c = ii(c, d, a, b, k[2], 15, 718787259);
        b = ii(b, c, d, a, k[9], 21, -343485551);

        x[0] = add32(a, x[0]);
        x[1] = add32(b, x[1]);
        x[2] = add32(c, x[2]);
        x[3] = add32(d, x[3]);
    }

    function md5blk(s) {
        var md5blks = [],
            i; /* Andy King said do it this way. */

        for (i = 0; i < 64; i += 4) {
            md5blks[i >> 2] = s.charCodeAt(i) + (s.charCodeAt(i + 1) << 8) + (s.charCodeAt(i + 2) << 16) + (s.charCodeAt(i + 3) << 24);
        }
        return md5blks;
    }

    function md5blk_array(a) {
        var md5blks = [],
            i; /* Andy King said do it this way. */

        for (i = 0; i < 64; i += 4) {
            md5blks[i >> 2] = a[i] + (a[i + 1] << 8) + (a[i + 2] << 16) + (a[i + 3] << 24);
        }
        return md5blks;
    }

    function md51(s) {
        var n = s.length,
            state = [1732584193, -271733879, -1732584194, 271733878],
            i,
            length,
            tail,
            tmp,
            lo,
            hi;

        for (i = 64; i <= n; i += 64) {
            md5cycle(state, md5blk(s.substring(i - 64, i)));
        }
        s = s.substring(i - 64);
        length = s.length;
        tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
        for (i = 0; i < length; i += 1) {
            tail[i >> 2] |= s.charCodeAt(i) << ((i % 4) << 3);
        }
        tail[i >> 2] |= 0x80 << ((i % 4) << 3);
        if (i > 55) {
            md5cycle(state, tail);
            for (i = 0; i < 16; i += 1) {
                tail[i] = 0;
            }
        }

        // Beware that the final length might not fit in 32 bits so we take care of that
        tmp = n * 8;
        tmp = tmp.toString(16).match(/(.*?)(.{0,8})$/);
        lo = parseInt(tmp[2], 16);
        hi = parseInt(tmp[1], 16) || 0;

        tail[14] = lo;
        tail[15] = hi;

        md5cycle(state, tail);
        return state;
    }

    function md51_array(a) {
        var n = a.length,
            state = [1732584193, -271733879, -1732584194, 271733878],
            i,
            length,
            tail,
            tmp,
            lo,
            hi;

        for (i = 64; i <= n; i += 64) {
            md5cycle(state, md5blk_array(a.subarray(i - 64, i)));
        }

        // Not sure if it is a bug, however IE10 will always produce a sub array of length 1
        // containing the last element of the parent array if the sub array specified starts
        // beyond the length of the parent array - weird.
        // https://connect.microsoft.com/IE/feedback/details/771452/typed-array-subarray-issue
        a = (i - 64) < n ? a.subarray(i - 64) : new Uint8Array(0);

        length = a.length;
        tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
        for (i = 0; i < length; i += 1) {
            tail[i >> 2] |= a[i] << ((i % 4) << 3);
        }

        tail[i >> 2] |= 0x80 << ((i % 4) << 3);
        if (i > 55) {
            md5cycle(state, tail);
            for (i = 0; i < 16; i += 1) {
                tail[i] = 0;
            }
        }

        // Beware that the final length might not fit in 32 bits so we take care of that
        tmp = n * 8;
        tmp = tmp.toString(16).match(/(.*?)(.{0,8})$/);
        lo = parseInt(tmp[2], 16);
        hi = parseInt(tmp[1], 16) || 0;

        tail[14] = lo;
        tail[15] = hi;

        md5cycle(state, tail);

        return state;
    }

    function rhex(n) {
        var s = '',
            j;
        for (j = 0; j < 4; j += 1) {
            s += hex_chr[(n >> (j * 8 + 4)) & 0x0F] + hex_chr[(n >> (j * 8)) & 0x0F];
        }
        return s;
    }

    function hex(x) {
        var i;
        for (i = 0; i < x.length; i += 1) {
            x[i] = rhex(x[i]);
        }
        return x.join('');
    }

    // In some cases the fast add32 function cannot be used..
    if (hex(md51('hello')) !== '5d41402abc4b2a76b9719d911017c592') {
        add32 = function (x, y) {
            var lsw = (x & 0xFFFF) + (y & 0xFFFF),
                msw = (x >> 16) + (y >> 16) + (lsw >> 16);
            return (msw << 16) | (lsw & 0xFFFF);
        };
    }

    // ---------------------------------------------------

    /**
     * ArrayBuffer slice polyfill.
     *
     * @see https://github.com/ttaubert/node-arraybuffer-slice
     */

    if (typeof ArrayBuffer !== 'undefined' && !ArrayBuffer.prototype.slice) {
        (function () {
            function clamp(val, length) {
                val = (val | 0) || 0;

                if (val < 0) {
                    return Math.max(val + length, 0);
                }

                return Math.min(val, length);
            }

            ArrayBuffer.prototype.slice = function (from, to) {
                var length = this.byteLength,
                    begin = clamp(from, length),
                    end = length,
                    num,
                    target,
                    targetArray,
                    sourceArray;

                if (to !== undefined) {
                    end = clamp(to, length);
                }

                if (begin > end) {
                    return new ArrayBuffer(0);
                }

                num = end - begin;
                target = new ArrayBuffer(num);
                targetArray = new Uint8Array(target);

                sourceArray = new Uint8Array(this, begin, num);
                targetArray.set(sourceArray);

                return target;
            };
        })();
    }

    // ---------------------------------------------------

    /**
     * Helpers.
     */

    function toUtf8(str) {
        if (/[\u0080-\uFFFF]/.test(str)) {
            str = unescape(encodeURIComponent(str));
        }

        return str;
    }

    function utf8Str2ArrayBuffer(str, returnUInt8Array) {
        var length = str.length,
           buff = new ArrayBuffer(length),
           arr = new Uint8Array(buff),
           i;

        for (i = 0; i < length; i += 1) {
            arr[i] = str.charCodeAt(i);
        }

        return returnUInt8Array ? arr : buff;
    }

    function arrayBuffer2Utf8Str(buff) {
        return String.fromCharCode.apply(null, new Uint8Array(buff));
    }

    function concatenateArrayBuffers(first, second, returnUInt8Array) {
        var result = new Uint8Array(first.byteLength + second.byteLength);

        result.set(new Uint8Array(first));
        result.set(new Uint8Array(second), first.byteLength);

        return returnUInt8Array ? result : result.buffer;
    }

    function hexToBinaryString(hex) {
        var bytes = [],
            length = hex.length,
            x;

        for (x = 0; x < length - 1; x += 2) {
            bytes.push(parseInt(hex.substr(x, 2), 16));
        }

        return String.fromCharCode.apply(String, bytes);
    }

    // ---------------------------------------------------

    /**
     * SparkMD5 OOP implementation.
     *
     * Use this class to perform an incremental md5, otherwise use the
     * static methods instead.
     */

    function SparkMD5() {
        // call reset to init the instance
        this.reset();
    }

    /**
     * Appends a string.
     * A conversion will be applied if an utf8 string is detected.
     *
     * @param {String} str The string to be appended
     *
     * @return {SparkMD5} The instance itself
     */
    SparkMD5.prototype.append = function (str) {
        // Converts the string to utf8 bytes if necessary
        // Then append as binary
        this.appendBinary(toUtf8(str));

        return this;
    };

    /**
     * Appends a binary string.
     *
     * @param {String} contents The binary string to be appended
     *
     * @return {SparkMD5} The instance itself
     */
    SparkMD5.prototype.appendBinary = function (contents) {
        this._buff += contents;
        this._length += contents.length;

        var length = this._buff.length,
            i;

        for (i = 64; i <= length; i += 64) {
            md5cycle(this._hash, md5blk(this._buff.substring(i - 64, i)));
        }

        this._buff = this._buff.substring(i - 64);

        return this;
    };

    /**
     * Finishes the incremental computation, reseting the internal state and
     * returning the result.
     *
     * @param {Boolean} raw True to get the raw string, false to get the hex string
     *
     * @return {String} The result
     */
    SparkMD5.prototype.end = function (raw) {
        var buff = this._buff,
            length = buff.length,
            i,
            tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
            ret;

        for (i = 0; i < length; i += 1) {
            tail[i >> 2] |= buff.charCodeAt(i) << ((i % 4) << 3);
        }

        this._finish(tail, length);
        ret = hex(this._hash);

        if (raw) {
            ret = hexToBinaryString(ret);
        }

        this.reset();

        return ret;
    };

    /**
     * Resets the internal state of the computation.
     *
     * @return {SparkMD5} The instance itself
     */
    SparkMD5.prototype.reset = function () {
        this._buff = '';
        this._length = 0;
        this._hash = [1732584193, -271733879, -1732584194, 271733878];

        return this;
    };

    /**
     * Gets the internal state of the computation.
     *
     * @return {Object} The state
     */
    SparkMD5.prototype.getState = function () {
        return {
            buff: this._buff,
            length: this._length,
            hash: this._hash
        };
    };

    /**
     * Gets the internal state of the computation.
     *
     * @param {Object} state The state
     *
     * @return {SparkMD5} The instance itself
     */
    SparkMD5.prototype.setState = function (state) {
        this._buff = state.buff;
        this._length = state.length;
        this._hash = state.hash;

        return this;
    };

    /**
     * Releases memory used by the incremental buffer and other additional
     * resources. If you plan to use the instance again, use reset instead.
     */
    SparkMD5.prototype.destroy = function () {
        delete this._hash;
        delete this._buff;
        delete this._length;
    };

    /**
     * Finish the final calculation based on the tail.
     *
     * @param {Array}  tail   The tail (will be modified)
     * @param {Number} length The length of the remaining buffer
     */
    SparkMD5.prototype._finish = function (tail, length) {
        var i = length,
            tmp,
            lo,
            hi;

        tail[i >> 2] |= 0x80 << ((i % 4) << 3);
        if (i > 55) {
            md5cycle(this._hash, tail);
            for (i = 0; i < 16; i += 1) {
                tail[i] = 0;
            }
        }

        // Do the final computation based on the tail and length
        // Beware that the final length may not fit in 32 bits so we take care of that
        tmp = this._length * 8;
        tmp = tmp.toString(16).match(/(.*?)(.{0,8})$/);
        lo = parseInt(tmp[2], 16);
        hi = parseInt(tmp[1], 16) || 0;

        tail[14] = lo;
        tail[15] = hi;
        md5cycle(this._hash, tail);
    };

    /**
     * Performs the md5 hash on a string.
     * A conversion will be applied if utf8 string is detected.
     *
     * @param {String}  str The string
     * @param {Boolean} raw True to get the raw string, false to get the hex string
     *
     * @return {String} The result
     */
    SparkMD5.hash = function (str, raw) {
        // Converts the string to utf8 bytes if necessary
        // Then compute it using the binary function
        return SparkMD5.hashBinary(toUtf8(str), raw);
    };

    /**
     * Performs the md5 hash on a binary string.
     *
     * @param {String}  content The binary string
     * @param {Boolean} raw     True to get the raw string, false to get the hex string
     *
     * @return {String} The result
     */
    SparkMD5.hashBinary = function (content, raw) {
        var hash = md51(content),
            ret = hex(hash);

        return raw ? hexToBinaryString(ret) : ret;
    };

    // ---------------------------------------------------

    /**
     * SparkMD5 OOP implementation for array buffers.
     *
     * Use this class to perform an incremental md5 ONLY for array buffers.
     */
    SparkMD5.ArrayBuffer = function () {
        // call reset to init the instance
        this.reset();
    };

    /**
     * Appends an array buffer.
     *
     * @param {ArrayBuffer} arr The array to be appended
     *
     * @return {SparkMD5.ArrayBuffer} The instance itself
     */
    SparkMD5.ArrayBuffer.prototype.append = function (arr) {
        var buff = concatenateArrayBuffers(this._buff.buffer, arr, true),
            length = buff.length,
            i;

        this._length += arr.byteLength;

        for (i = 64; i <= length; i += 64) {
            md5cycle(this._hash, md5blk_array(buff.subarray(i - 64, i)));
        }

        this._buff = (i - 64) < length ? new Uint8Array(buff.buffer.slice(i - 64)) : new Uint8Array(0);

        return this;
    };

    /**
     * Finishes the incremental computation, reseting the internal state and
     * returning the result.
     *
     * @param {Boolean} raw True to get the raw string, false to get the hex string
     *
     * @return {String} The result
     */
    SparkMD5.ArrayBuffer.prototype.end = function (raw) {
        var buff = this._buff,
            length = buff.length,
            tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
            i,
            ret;

        for (i = 0; i < length; i += 1) {
            tail[i >> 2] |= buff[i] << ((i % 4) << 3);
        }

        this._finish(tail, length);
        ret = hex(this._hash);

        if (raw) {
            ret = hexToBinaryString(ret);
        }

        this.reset();

        return ret;
    };

    /**
     * Resets the internal state of the computation.
     *
     * @return {SparkMD5.ArrayBuffer} The instance itself
     */
    SparkMD5.ArrayBuffer.prototype.reset = function () {
        this._buff = new Uint8Array(0);
        this._length = 0;
        this._hash = [1732584193, -271733879, -1732584194, 271733878];

        return this;
    };

    /**
     * Gets the internal state of the computation.
     *
     * @return {Object} The state
     */
    SparkMD5.ArrayBuffer.prototype.getState = function () {
        var state = SparkMD5.prototype.getState.call(this);

        // Convert buffer to a string
        state.buff = arrayBuffer2Utf8Str(state.buff);

        return state;
    };

    /**
     * Gets the internal state of the computation.
     *
     * @param {Object} state The state
     *
     * @return {SparkMD5.ArrayBuffer} The instance itself
     */
    SparkMD5.ArrayBuffer.prototype.setState = function (state) {
        // Convert string to buffer
        state.buff = utf8Str2ArrayBuffer(state.buff, true);

        return SparkMD5.prototype.setState.call(this, state);
    };

    SparkMD5.ArrayBuffer.prototype.destroy = SparkMD5.prototype.destroy;

    SparkMD5.ArrayBuffer.prototype._finish = SparkMD5.prototype._finish;

    /**
     * Performs the md5 hash on an array buffer.
     *
     * @param {ArrayBuffer} arr The array buffer
     * @param {Boolean}     raw True to get the raw string, false to get the hex one
     *
     * @return {String} The result
     */
    SparkMD5.ArrayBuffer.hash = function (arr, raw) {
        var hash = md51_array(new Uint8Array(arr)),
            ret = hex(hash);

        return raw ? hexToBinaryString(ret) : ret;
    };

    return SparkMD5;
}));

},{}],80:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

var Buffer = require('buffer').Buffer;

var isBufferEncoding = Buffer.isEncoding
  || function(encoding) {
       switch (encoding && encoding.toLowerCase()) {
         case 'hex': case 'utf8': case 'utf-8': case 'ascii': case 'binary': case 'base64': case 'ucs2': case 'ucs-2': case 'utf16le': case 'utf-16le': case 'raw': return true;
         default: return false;
       }
     }


function assertEncoding(encoding) {
  if (encoding && !isBufferEncoding(encoding)) {
    throw new Error('Unknown encoding: ' + encoding);
  }
}

// StringDecoder provides an interface for efficiently splitting a series of
// buffers into a series of JS strings without breaking apart multi-byte
// characters. CESU-8 is handled as part of the UTF-8 encoding.
//
// @TODO Handling all encodings inside a single object makes it very difficult
// to reason about this code, so it should be split up in the future.
// @TODO There should be a utf8-strict encoding that rejects invalid UTF-8 code
// points as used by CESU-8.
var StringDecoder = exports.StringDecoder = function(encoding) {
  this.encoding = (encoding || 'utf8').toLowerCase().replace(/[-_]/, '');
  assertEncoding(encoding);
  switch (this.encoding) {
    case 'utf8':
      // CESU-8 represents each of Surrogate Pair by 3-bytes
      this.surrogateSize = 3;
      break;
    case 'ucs2':
    case 'utf16le':
      // UTF-16 represents each of Surrogate Pair by 2-bytes
      this.surrogateSize = 2;
      this.detectIncompleteChar = utf16DetectIncompleteChar;
      break;
    case 'base64':
      // Base-64 stores 3 bytes in 4 chars, and pads the remainder.
      this.surrogateSize = 3;
      this.detectIncompleteChar = base64DetectIncompleteChar;
      break;
    default:
      this.write = passThroughWrite;
      return;
  }

  // Enough space to store all bytes of a single character. UTF-8 needs 4
  // bytes, but CESU-8 may require up to 6 (3 bytes per surrogate).
  this.charBuffer = new Buffer(6);
  // Number of bytes received for the current incomplete multi-byte character.
  this.charReceived = 0;
  // Number of bytes expected for the current incomplete multi-byte character.
  this.charLength = 0;
};


// write decodes the given buffer and returns it as JS string that is
// guaranteed to not contain any partial multi-byte characters. Any partial
// character found at the end of the buffer is buffered up, and will be
// returned when calling write again with the remaining bytes.
//
// Note: Converting a Buffer containing an orphan surrogate to a String
// currently works, but converting a String to a Buffer (via `new Buffer`, or
// Buffer#write) will replace incomplete surrogates with the unicode
// replacement character. See https://codereview.chromium.org/121173009/ .
StringDecoder.prototype.write = function(buffer) {
  var charStr = '';
  // if our last write ended with an incomplete multibyte character
  while (this.charLength) {
    // determine how many remaining bytes this buffer has to offer for this char
    var available = (buffer.length >= this.charLength - this.charReceived) ?
        this.charLength - this.charReceived :
        buffer.length;

    // add the new bytes to the char buffer
    buffer.copy(this.charBuffer, this.charReceived, 0, available);
    this.charReceived += available;

    if (this.charReceived < this.charLength) {
      // still not enough chars in this buffer? wait for more ...
      return '';
    }

    // remove bytes belonging to the current character from the buffer
    buffer = buffer.slice(available, buffer.length);

    // get the character that was split
    charStr = this.charBuffer.slice(0, this.charLength).toString(this.encoding);

    // CESU-8: lead surrogate (D800-DBFF) is also the incomplete character
    var charCode = charStr.charCodeAt(charStr.length - 1);
    if (charCode >= 0xD800 && charCode <= 0xDBFF) {
      this.charLength += this.surrogateSize;
      charStr = '';
      continue;
    }
    this.charReceived = this.charLength = 0;

    // if there are no more bytes in this buffer, just emit our char
    if (buffer.length === 0) {
      return charStr;
    }
    break;
  }

  // determine and set charLength / charReceived
  this.detectIncompleteChar(buffer);

  var end = buffer.length;
  if (this.charLength) {
    // buffer the incomplete character bytes we got
    buffer.copy(this.charBuffer, 0, buffer.length - this.charReceived, end);
    end -= this.charReceived;
  }

  charStr += buffer.toString(this.encoding, 0, end);

  var end = charStr.length - 1;
  var charCode = charStr.charCodeAt(end);
  // CESU-8: lead surrogate (D800-DBFF) is also the incomplete character
  if (charCode >= 0xD800 && charCode <= 0xDBFF) {
    var size = this.surrogateSize;
    this.charLength += size;
    this.charReceived += size;
    this.charBuffer.copy(this.charBuffer, size, 0, size);
    buffer.copy(this.charBuffer, 0, 0, size);
    return charStr.substring(0, end);
  }

  // or just emit the charStr
  return charStr;
};

// detectIncompleteChar determines if there is an incomplete UTF-8 character at
// the end of the given buffer. If so, it sets this.charLength to the byte
// length that character, and sets this.charReceived to the number of bytes
// that are available for this character.
StringDecoder.prototype.detectIncompleteChar = function(buffer) {
  // determine how many bytes we have to check at the end of this buffer
  var i = (buffer.length >= 3) ? 3 : buffer.length;

  // Figure out if one of the last i bytes of our buffer announces an
  // incomplete char.
  for (; i > 0; i--) {
    var c = buffer[buffer.length - i];

    // See http://en.wikipedia.org/wiki/UTF-8#Description

    // 110XXXXX
    if (i == 1 && c >> 5 == 0x06) {
      this.charLength = 2;
      break;
    }

    // 1110XXXX
    if (i <= 2 && c >> 4 == 0x0E) {
      this.charLength = 3;
      break;
    }

    // 11110XXX
    if (i <= 3 && c >> 3 == 0x1E) {
      this.charLength = 4;
      break;
    }
  }
  this.charReceived = i;
};

StringDecoder.prototype.end = function(buffer) {
  var res = '';
  if (buffer && buffer.length)
    res = this.write(buffer);

  if (this.charReceived) {
    var cr = this.charReceived;
    var buf = this.charBuffer;
    var enc = this.encoding;
    res += buf.slice(0, cr).toString(enc);
  }

  return res;
};

function passThroughWrite(buffer) {
  return buffer.toString(this.encoding);
}

function utf16DetectIncompleteChar(buffer) {
  this.charReceived = buffer.length % 2;
  this.charLength = this.charReceived ? 2 : 0;
}

function base64DetectIncompleteChar(buffer) {
  this.charReceived = buffer.length % 3;
  this.charLength = this.charReceived ? 3 : 0;
}

},{"buffer":105}],81:[function(require,module,exports){
'use strict';

function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }

var ltgt = _interopDefault(require('ltgt'));
var events = _interopDefault(require('events'));
var inherits = _interopDefault(require('inherits'));
var Codec = _interopDefault(require('level-codec'));
var ReadableStreamCore = _interopDefault(require('readable-stream'));

function isFunction(f) {
  return 'function' === typeof f;
}

function getPrefix(db) {
  if (isFunction(db.prefix)) {
    return db.prefix();
  }
  return db;
}

function clone(_obj) {
  var obj = {};
  for(var k in _obj) {
    obj[k] = _obj[k];
  }
  return obj;
}

function nut(db, precodec, codec) {
  function encodePrefix(prefix, key, opts1, opts2) {
    return precodec.encode([ prefix, codec.encodeKey(key, opts1, opts2 ) ]);
  }

  function addEncodings(op, prefix) {
    if(prefix && prefix.options) {
      op.keyEncoding =
        op.keyEncoding || prefix.options.keyEncoding;
      op.valueEncoding =
        op.valueEncoding || prefix.options.valueEncoding;
    }
    return op;
  }

  db.open(function () { /* no-op */});

  return {
    apply: function (ops, opts, cb) {
      opts = opts || {};

      var batch = [];
      var i = -1;
      var len = ops.length;

      while (++i < len) {
        var op = ops[i];
        addEncodings(op, op.prefix);
        op.prefix = getPrefix(op.prefix);
        batch.push({
          key: encodePrefix(op.prefix, op.key, opts, op),
          value: op.type !== 'del' && codec.encodeValue(op.value, opts, op),
          type: op.type
        });
      }
      db.db.batch(batch, opts, cb);
    },
    get: function (key, prefix, opts, cb) {
      opts.asBuffer = codec.valueAsBuffer(opts);
      return db.db.get(
        encodePrefix(prefix, key, opts),
        opts,
        function (err, value) {
          if (err) {
            cb(err);
          } else {
            cb(null, codec.decodeValue(value, opts));
          }
        }
      );
    },
    createDecoder: function (opts) {
      return function (key, value) {
        return {
          key: codec.decodeKey(precodec.decode(key)[1], opts),
          value: codec.decodeValue(value, opts)
        };
      };
    },
    isClosed: function isClosed() {
      return db.isClosed();
    },
    close: function close(cb) {
      return db.close(cb);
    },
    iterator: function (_opts) {
      var opts = clone(_opts || {});
      var prefix = _opts.prefix || [];

      function encodeKey(key) {
        return encodePrefix(prefix, key, opts, {});
      }

      ltgt.toLtgt(_opts, opts, encodeKey, precodec.lowerBound, precodec.upperBound);

      // if these legacy values are in the options, remove them

      opts.prefix = null;

      //************************************************
      //hard coded defaults, for now...
      //TODO: pull defaults and encoding out of levelup.
      opts.keyAsBuffer = opts.valueAsBuffer = false;
      //************************************************


      //this is vital, otherwise limit: undefined will
      //create an empty stream.
      /* istanbul ignore next */
      if ('number' !== typeof opts.limit) {
        opts.limit = -1;
      }

      opts.keyAsBuffer = precodec.buffer;
      opts.valueAsBuffer = codec.valueAsBuffer(opts);

      function wrapIterator(iterator) {
        return {
          next: function (cb) {
            return iterator.next(cb);
          },
          end: function (cb) {
            iterator.end(cb);
          }
        };
      }

      return wrapIterator(db.db.iterator(opts));
    }
  };
}

function NotFoundError() {
  Error.call(this);
}

inherits(NotFoundError, Error);

NotFoundError.prototype.name = 'NotFoundError';

var EventEmitter = events.EventEmitter;
var version = "6.5.4";

var NOT_FOUND_ERROR = new NotFoundError();

var sublevel = function (nut, prefix, createStream, options) {
  var emitter = new EventEmitter();
  emitter.sublevels = {};
  emitter.options = options;

  emitter.version = version;

  emitter.methods = {};
  prefix = prefix || [];

  function mergeOpts(opts) {
    var o = {};
    var k;
    if (options) {
      for (k in options) {
        if (typeof options[k] !== 'undefined') {
          o[k] = options[k];
        }
      }
    }
    if (opts) {
      for (k in opts) {
        if (typeof opts[k] !== 'undefined') {
          o[k] = opts[k];
        }
      }
    }
    return o;
  }

  emitter.put = function (key, value, opts, cb) {
    if ('function' === typeof opts) {
      cb = opts;
      opts = {};
    }

    nut.apply([{
      key: key, value: value,
      prefix: prefix.slice(), type: 'put'
    }], mergeOpts(opts), function (err) {
      /* istanbul ignore next */
      if (err) {
        return cb(err);
      }
      emitter.emit('put', key, value);
      cb(null);
    });
  };

  emitter.prefix = function () {
    return prefix.slice();
  };

  emitter.batch = function (ops, opts, cb) {
    if ('function' === typeof opts) {
      cb = opts;
      opts = {};
    }

    ops = ops.map(function (op) {
      return {
        key: op.key,
        value: op.value,
        prefix: op.prefix || prefix,
        keyEncoding: op.keyEncoding,    // *
        valueEncoding: op.valueEncoding,  // * (TODO: encodings on sublevel)
        type: op.type
      };
    });

    nut.apply(ops, mergeOpts(opts), function (err) {
      /* istanbul ignore next */
      if (err) {
        return cb(err);
      }
      emitter.emit('batch', ops);
      cb(null);
    });
  };

  emitter.get = function (key, opts, cb) {
    /* istanbul ignore else */
    if ('function' === typeof opts) {
      cb = opts;
      opts = {};
    }
    nut.get(key, prefix, mergeOpts(opts), function (err, value) {
      if (err) {
        cb(NOT_FOUND_ERROR);
      } else {
        cb(null, value);
      }
    });
  };

  emitter.sublevel = function (name, opts) {
    return emitter.sublevels[name] =
      emitter.sublevels[name] || sublevel(nut, prefix.concat(name), createStream, mergeOpts(opts));
  };

  emitter.readStream = emitter.createReadStream = function (opts) {
    opts = mergeOpts(opts);
    opts.prefix = prefix;
    var stream;
    var it = nut.iterator(opts);

    stream = createStream(opts, nut.createDecoder(opts));
    stream.setIterator(it);

    return stream;
  };

  emitter.close = function (cb) {
    nut.close(cb);
  };

  emitter.isOpen = nut.isOpen;
  emitter.isClosed = nut.isClosed;

  return emitter;
};

/* Copyright (c) 2012-2014 LevelUP contributors
 * See list at <https://github.com/rvagg/node-levelup#contributing>
 * MIT License <https://github.com/rvagg/node-levelup/blob/master/LICENSE.md>
 */

// NOTE: we are fixed to readable-stream@1.0.x for now
// for pure Streams2 across Node versions
var Readable = ReadableStreamCore.Readable;

function ReadStream(options, makeData) {
  if (!(this instanceof ReadStream)) {
    return new ReadStream(options, makeData);
  }

  Readable.call(this, { objectMode: true, highWaterMark: options.highWaterMark });

  // purely to keep `db` around until we're done so it's not GCed if the user doesn't keep a ref

  this._waiting = false;
  this._options = options;
  this._makeData = makeData;
}

inherits(ReadStream, Readable);

ReadStream.prototype.setIterator = function (it) {
  this._iterator = it;
  /* istanbul ignore if */
  if (this._destroyed) {
    return it.end(function () {});
  }
  /* istanbul ignore if */
  if (this._waiting) {
    this._waiting = false;
    return this._read();
  }
  return this;
};

ReadStream.prototype._read = function read() {
  var self = this;
  /* istanbul ignore if */
  if (self._destroyed) {
    return;
  }
  /* istanbul ignore if */
  if (!self._iterator) {
    return this._waiting = true;
  }

  self._iterator.next(function (err, key, value) {
    if (err || (key === undefined && value === undefined)) {
      if (!err && !self._destroyed) {
        self.push(null);
      }
      return self._cleanup(err);
    }


    value = self._makeData(key, value);
    if (!self._destroyed) {
      self.push(value);
    }
  });
};

ReadStream.prototype._cleanup = function (err) {
  if (this._destroyed) {
    return;
  }

  this._destroyed = true;

  var self = this;
  /* istanbul ignore if */
  if (err) {
    self.emit('error', err);
  }

  /* istanbul ignore else */
  if (self._iterator) {
    self._iterator.end(function () {
      self._iterator = null;
      self.emit('close');
    });
  } else {
    self.emit('close');
  }
};

ReadStream.prototype.destroy = function () {
  this._cleanup();
};

var precodec = {
  encode: function (decodedKey) {
    return '\xff' + decodedKey[0] + '\xff' + decodedKey[1];
  },
  decode: function (encodedKeyAsBuffer) {
    var str = encodedKeyAsBuffer.toString();
    var idx = str.indexOf('\xff', 1);
    return [str.substring(1, idx), str.substring(idx + 1)];
  },
  lowerBound: '\x00',
  upperBound: '\xff'
};

var codec = new Codec();

function sublevelPouch(db) {
  return sublevel(nut(db, precodec, codec), [], ReadStream, db.options);
}

module.exports = sublevelPouch;
},{"events":107,"inherits":28,"level-codec":82,"ltgt":47,"readable-stream":89}],82:[function(require,module,exports){
arguments[4][30][0].apply(exports,arguments)
},{"./lib/encodings":83,"dup":30}],83:[function(require,module,exports){
(function (Buffer){

exports.utf8 = exports['utf-8'] = {
  encode: function(data){
    return isBinary(data)
      ? data
      : String(data);
  },
  decode: identity,
  buffer: false,
  type: 'utf8'
};

exports.json = {
  encode: JSON.stringify,
  decode: JSON.parse,
  buffer: false,
  type: 'json'
};

exports.binary = {
  encode: function(data){
    return isBinary(data)
      ? data
      : new Buffer(data);      
  },
  decode: identity,
  buffer: true,
  type: 'binary'
};

exports.none = {
  encode: function(data){
    return data;
  },
  decode: function(data){
    return data;
  },
  buffer: false,
  type: 'id'
};

exports.id = exports.none;

var bufferEncodings = [
  'hex',
  'ascii',
  'base64',
  'ucs2',
  'ucs-2',
  'utf16le',
  'utf-16le'
];

bufferEncodings.forEach(function(type){
  exports[type] = {
    encode: function(data){
      return isBinary(data)
        ? data
        : new Buffer(data, type);
    },
    decode: function(buffer){
      return buffer.toString(type);
    },
    buffer: true,
    type: type
  };
});

function identity(value){
  return value;
}

function isBinary(data){
  return data === undefined
    || data === null
    || Buffer.isBuffer(data);
}


}).call(this,require("buffer").Buffer)
},{"buffer":105}],84:[function(require,module,exports){
arguments[4][72][0].apply(exports,arguments)
},{"./_stream_readable":86,"./_stream_writable":88,"_process":113,"core-util-is":6,"dup":72,"inherits":28}],85:[function(require,module,exports){
arguments[4][73][0].apply(exports,arguments)
},{"./_stream_transform":87,"core-util-is":6,"dup":73,"inherits":28}],86:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

module.exports = Readable;

/*<replacement>*/
var isArray = require('isarray');
/*</replacement>*/


/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Readable.ReadableState = ReadableState;

var EE = require('events').EventEmitter;

/*<replacement>*/
if (!EE.listenerCount) EE.listenerCount = function(emitter, type) {
  return emitter.listeners(type).length;
};
/*</replacement>*/

var Stream = require('stream');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var StringDecoder;

util.inherits(Readable, Stream);

function ReadableState(options, stream) {
  options = options || {};

  // the point at which it stops calling _read() to fill the buffer
  // Note: 0 is a valid value, means "don't call _read preemptively ever"
  var hwm = options.highWaterMark;
  this.highWaterMark = (hwm || hwm === 0) ? hwm : 16 * 1024;

  // cast to ints.
  this.highWaterMark = ~~this.highWaterMark;

  this.buffer = [];
  this.length = 0;
  this.pipes = null;
  this.pipesCount = 0;
  this.flowing = false;
  this.ended = false;
  this.endEmitted = false;
  this.reading = false;

  // In streams that never have any data, and do push(null) right away,
  // the consumer can miss the 'end' event if they do some I/O before
  // consuming the stream.  So, we don't emit('end') until some reading
  // happens.
  this.calledRead = false;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, becuase any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // whenever we return null, then we set a flag to say
  // that we're awaiting a 'readable' event emission.
  this.needReadable = false;
  this.emittedReadable = false;
  this.readableListening = false;


  // object stream flag. Used to make read(n) ignore n and to
  // make all the buffer merging and length checks go away
  this.objectMode = !!options.objectMode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // when piping, we only care about 'readable' events that happen
  // after read()ing all the bytes and not getting any pushback.
  this.ranOut = false;

  // the number of writers that are awaiting a drain event in .pipe()s
  this.awaitDrain = 0;

  // if true, a maybeReadMore has been scheduled
  this.readingMore = false;

  this.decoder = null;
  this.encoding = null;
  if (options.encoding) {
    if (!StringDecoder)
      StringDecoder = require('string_decoder/').StringDecoder;
    this.decoder = new StringDecoder(options.encoding);
    this.encoding = options.encoding;
  }
}

function Readable(options) {
  if (!(this instanceof Readable))
    return new Readable(options);

  this._readableState = new ReadableState(options, this);

  // legacy
  this.readable = true;

  Stream.call(this);
}

// Manually shove something into the read() buffer.
// This returns true if the highWaterMark has not been hit yet,
// similar to how Writable.write() returns true if you should
// write() some more.
Readable.prototype.push = function(chunk, encoding) {
  var state = this._readableState;

  if (typeof chunk === 'string' && !state.objectMode) {
    encoding = encoding || state.defaultEncoding;
    if (encoding !== state.encoding) {
      chunk = new Buffer(chunk, encoding);
      encoding = '';
    }
  }

  return readableAddChunk(this, state, chunk, encoding, false);
};

// Unshift should *always* be something directly out of read()
Readable.prototype.unshift = function(chunk) {
  var state = this._readableState;
  return readableAddChunk(this, state, chunk, '', true);
};

function readableAddChunk(stream, state, chunk, encoding, addToFront) {
  var er = chunkInvalid(state, chunk);
  if (er) {
    stream.emit('error', er);
  } else if (chunk === null || chunk === undefined) {
    state.reading = false;
    if (!state.ended)
      onEofChunk(stream, state);
  } else if (state.objectMode || chunk && chunk.length > 0) {
    if (state.ended && !addToFront) {
      var e = new Error('stream.push() after EOF');
      stream.emit('error', e);
    } else if (state.endEmitted && addToFront) {
      var e = new Error('stream.unshift() after end event');
      stream.emit('error', e);
    } else {
      if (state.decoder && !addToFront && !encoding)
        chunk = state.decoder.write(chunk);

      // update the buffer info.
      state.length += state.objectMode ? 1 : chunk.length;
      if (addToFront) {
        state.buffer.unshift(chunk);
      } else {
        state.reading = false;
        state.buffer.push(chunk);
      }

      if (state.needReadable)
        emitReadable(stream);

      maybeReadMore(stream, state);
    }
  } else if (!addToFront) {
    state.reading = false;
  }

  return needMoreData(state);
}



// if it's past the high water mark, we can push in some more.
// Also, if we have no data yet, we can stand some
// more bytes.  This is to work around cases where hwm=0,
// such as the repl.  Also, if the push() triggered a
// readable event, and the user called read(largeNumber) such that
// needReadable was set, then we ought to push more, so that another
// 'readable' event will be triggered.
function needMoreData(state) {
  return !state.ended &&
         (state.needReadable ||
          state.length < state.highWaterMark ||
          state.length === 0);
}

// backwards compatibility.
Readable.prototype.setEncoding = function(enc) {
  if (!StringDecoder)
    StringDecoder = require('string_decoder/').StringDecoder;
  this._readableState.decoder = new StringDecoder(enc);
  this._readableState.encoding = enc;
};

// Don't raise the hwm > 128MB
var MAX_HWM = 0x800000;
function roundUpToNextPowerOf2(n) {
  if (n >= MAX_HWM) {
    n = MAX_HWM;
  } else {
    // Get the next highest power of 2
    n--;
    for (var p = 1; p < 32; p <<= 1) n |= n >> p;
    n++;
  }
  return n;
}

function howMuchToRead(n, state) {
  if (state.length === 0 && state.ended)
    return 0;

  if (state.objectMode)
    return n === 0 ? 0 : 1;

  if (n === null || isNaN(n)) {
    // only flow one buffer at a time
    if (state.flowing && state.buffer.length)
      return state.buffer[0].length;
    else
      return state.length;
  }

  if (n <= 0)
    return 0;

  // If we're asking for more than the target buffer level,
  // then raise the water mark.  Bump up to the next highest
  // power of 2, to prevent increasing it excessively in tiny
  // amounts.
  if (n > state.highWaterMark)
    state.highWaterMark = roundUpToNextPowerOf2(n);

  // don't have that much.  return null, unless we've ended.
  if (n > state.length) {
    if (!state.ended) {
      state.needReadable = true;
      return 0;
    } else
      return state.length;
  }

  return n;
}

// you can override either this method, or the async _read(n) below.
Readable.prototype.read = function(n) {
  var state = this._readableState;
  state.calledRead = true;
  var nOrig = n;
  var ret;

  if (typeof n !== 'number' || n > 0)
    state.emittedReadable = false;

  // if we're doing read(0) to trigger a readable event, but we
  // already have a bunch of data in the buffer, then just trigger
  // the 'readable' event and move on.
  if (n === 0 &&
      state.needReadable &&
      (state.length >= state.highWaterMark || state.ended)) {
    emitReadable(this);
    return null;
  }

  n = howMuchToRead(n, state);

  // if we've ended, and we're now clear, then finish it up.
  if (n === 0 && state.ended) {
    ret = null;

    // In cases where the decoder did not receive enough data
    // to produce a full chunk, then immediately received an
    // EOF, state.buffer will contain [<Buffer >, <Buffer 00 ...>].
    // howMuchToRead will see this and coerce the amount to
    // read to zero (because it's looking at the length of the
    // first <Buffer > in state.buffer), and we'll end up here.
    //
    // This can only happen via state.decoder -- no other venue
    // exists for pushing a zero-length chunk into state.buffer
    // and triggering this behavior. In this case, we return our
    // remaining data and end the stream, if appropriate.
    if (state.length > 0 && state.decoder) {
      ret = fromList(n, state);
      state.length -= ret.length;
    }

    if (state.length === 0)
      endReadable(this);

    return ret;
  }

  // All the actual chunk generation logic needs to be
  // *below* the call to _read.  The reason is that in certain
  // synthetic stream cases, such as passthrough streams, _read
  // may be a completely synchronous operation which may change
  // the state of the read buffer, providing enough data when
  // before there was *not* enough.
  //
  // So, the steps are:
  // 1. Figure out what the state of things will be after we do
  // a read from the buffer.
  //
  // 2. If that resulting state will trigger a _read, then call _read.
  // Note that this may be asynchronous, or synchronous.  Yes, it is
  // deeply ugly to write APIs this way, but that still doesn't mean
  // that the Readable class should behave improperly, as streams are
  // designed to be sync/async agnostic.
  // Take note if the _read call is sync or async (ie, if the read call
  // has returned yet), so that we know whether or not it's safe to emit
  // 'readable' etc.
  //
  // 3. Actually pull the requested chunks out of the buffer and return.

  // if we need a readable event, then we need to do some reading.
  var doRead = state.needReadable;

  // if we currently have less than the highWaterMark, then also read some
  if (state.length - n <= state.highWaterMark)
    doRead = true;

  // however, if we've ended, then there's no point, and if we're already
  // reading, then it's unnecessary.
  if (state.ended || state.reading)
    doRead = false;

  if (doRead) {
    state.reading = true;
    state.sync = true;
    // if the length is currently zero, then we *need* a readable event.
    if (state.length === 0)
      state.needReadable = true;
    // call internal read method
    this._read(state.highWaterMark);
    state.sync = false;
  }

  // If _read called its callback synchronously, then `reading`
  // will be false, and we need to re-evaluate how much data we
  // can return to the user.
  if (doRead && !state.reading)
    n = howMuchToRead(nOrig, state);

  if (n > 0)
    ret = fromList(n, state);
  else
    ret = null;

  if (ret === null) {
    state.needReadable = true;
    n = 0;
  }

  state.length -= n;

  // If we have nothing in the buffer, then we want to know
  // as soon as we *do* get something into the buffer.
  if (state.length === 0 && !state.ended)
    state.needReadable = true;

  // If we happened to read() exactly the remaining amount in the
  // buffer, and the EOF has been seen at this point, then make sure
  // that we emit 'end' on the very next tick.
  if (state.ended && !state.endEmitted && state.length === 0)
    endReadable(this);

  return ret;
};

function chunkInvalid(state, chunk) {
  var er = null;
  if (!Buffer.isBuffer(chunk) &&
      'string' !== typeof chunk &&
      chunk !== null &&
      chunk !== undefined &&
      !state.objectMode) {
    er = new TypeError('Invalid non-string/buffer chunk');
  }
  return er;
}


function onEofChunk(stream, state) {
  if (state.decoder && !state.ended) {
    var chunk = state.decoder.end();
    if (chunk && chunk.length) {
      state.buffer.push(chunk);
      state.length += state.objectMode ? 1 : chunk.length;
    }
  }
  state.ended = true;

  // if we've ended and we have some data left, then emit
  // 'readable' now to make sure it gets picked up.
  if (state.length > 0)
    emitReadable(stream);
  else
    endReadable(stream);
}

// Don't emit readable right away in sync mode, because this can trigger
// another read() call => stack overflow.  This way, it might trigger
// a nextTick recursion warning, but that's not so bad.
function emitReadable(stream) {
  var state = stream._readableState;
  state.needReadable = false;
  if (state.emittedReadable)
    return;

  state.emittedReadable = true;
  if (state.sync)
    process.nextTick(function() {
      emitReadable_(stream);
    });
  else
    emitReadable_(stream);
}

function emitReadable_(stream) {
  stream.emit('readable');
}


// at this point, the user has presumably seen the 'readable' event,
// and called read() to consume some data.  that may have triggered
// in turn another _read(n) call, in which case reading = true if
// it's in progress.
// However, if we're not ended, or reading, and the length < hwm,
// then go ahead and try to read some more preemptively.
function maybeReadMore(stream, state) {
  if (!state.readingMore) {
    state.readingMore = true;
    process.nextTick(function() {
      maybeReadMore_(stream, state);
    });
  }
}

function maybeReadMore_(stream, state) {
  var len = state.length;
  while (!state.reading && !state.flowing && !state.ended &&
         state.length < state.highWaterMark) {
    stream.read(0);
    if (len === state.length)
      // didn't get any data, stop spinning.
      break;
    else
      len = state.length;
  }
  state.readingMore = false;
}

// abstract method.  to be overridden in specific implementation classes.
// call cb(er, data) where data is <= n in length.
// for virtual (non-string, non-buffer) streams, "length" is somewhat
// arbitrary, and perhaps not very meaningful.
Readable.prototype._read = function(n) {
  this.emit('error', new Error('not implemented'));
};

Readable.prototype.pipe = function(dest, pipeOpts) {
  var src = this;
  var state = this._readableState;

  switch (state.pipesCount) {
    case 0:
      state.pipes = dest;
      break;
    case 1:
      state.pipes = [state.pipes, dest];
      break;
    default:
      state.pipes.push(dest);
      break;
  }
  state.pipesCount += 1;

  var doEnd = (!pipeOpts || pipeOpts.end !== false) &&
              dest !== process.stdout &&
              dest !== process.stderr;

  var endFn = doEnd ? onend : cleanup;
  if (state.endEmitted)
    process.nextTick(endFn);
  else
    src.once('end', endFn);

  dest.on('unpipe', onunpipe);
  function onunpipe(readable) {
    if (readable !== src) return;
    cleanup();
  }

  function onend() {
    dest.end();
  }

  // when the dest drains, it reduces the awaitDrain counter
  // on the source.  This would be more elegant with a .once()
  // handler in flow(), but adding and removing repeatedly is
  // too slow.
  var ondrain = pipeOnDrain(src);
  dest.on('drain', ondrain);

  function cleanup() {
    // cleanup event handlers once the pipe is broken
    dest.removeListener('close', onclose);
    dest.removeListener('finish', onfinish);
    dest.removeListener('drain', ondrain);
    dest.removeListener('error', onerror);
    dest.removeListener('unpipe', onunpipe);
    src.removeListener('end', onend);
    src.removeListener('end', cleanup);

    // if the reader is waiting for a drain event from this
    // specific writer, then it would cause it to never start
    // flowing again.
    // So, if this is awaiting a drain, then we just call it now.
    // If we don't know, then assume that we are waiting for one.
    if (!dest._writableState || dest._writableState.needDrain)
      ondrain();
  }

  // if the dest has an error, then stop piping into it.
  // however, don't suppress the throwing behavior for this.
  function onerror(er) {
    unpipe();
    dest.removeListener('error', onerror);
    if (EE.listenerCount(dest, 'error') === 0)
      dest.emit('error', er);
  }
  // This is a brutally ugly hack to make sure that our error handler
  // is attached before any userland ones.  NEVER DO THIS.
  if (!dest._events || !dest._events.error)
    dest.on('error', onerror);
  else if (isArray(dest._events.error))
    dest._events.error.unshift(onerror);
  else
    dest._events.error = [onerror, dest._events.error];



  // Both close and finish should trigger unpipe, but only once.
  function onclose() {
    dest.removeListener('finish', onfinish);
    unpipe();
  }
  dest.once('close', onclose);
  function onfinish() {
    dest.removeListener('close', onclose);
    unpipe();
  }
  dest.once('finish', onfinish);

  function unpipe() {
    src.unpipe(dest);
  }

  // tell the dest that it's being piped to
  dest.emit('pipe', src);

  // start the flow if it hasn't been started already.
  if (!state.flowing) {
    // the handler that waits for readable events after all
    // the data gets sucked out in flow.
    // This would be easier to follow with a .once() handler
    // in flow(), but that is too slow.
    this.on('readable', pipeOnReadable);

    state.flowing = true;
    process.nextTick(function() {
      flow(src);
    });
  }

  return dest;
};

function pipeOnDrain(src) {
  return function() {
    var dest = this;
    var state = src._readableState;
    state.awaitDrain--;
    if (state.awaitDrain === 0)
      flow(src);
  };
}

function flow(src) {
  var state = src._readableState;
  var chunk;
  state.awaitDrain = 0;

  function write(dest, i, list) {
    var written = dest.write(chunk);
    if (false === written) {
      state.awaitDrain++;
    }
  }

  while (state.pipesCount && null !== (chunk = src.read())) {

    if (state.pipesCount === 1)
      write(state.pipes, 0, null);
    else
      forEach(state.pipes, write);

    src.emit('data', chunk);

    // if anyone needs a drain, then we have to wait for that.
    if (state.awaitDrain > 0)
      return;
  }

  // if every destination was unpiped, either before entering this
  // function, or in the while loop, then stop flowing.
  //
  // NB: This is a pretty rare edge case.
  if (state.pipesCount === 0) {
    state.flowing = false;

    // if there were data event listeners added, then switch to old mode.
    if (EE.listenerCount(src, 'data') > 0)
      emitDataEvents(src);
    return;
  }

  // at this point, no one needed a drain, so we just ran out of data
  // on the next readable event, start it over again.
  state.ranOut = true;
}

function pipeOnReadable() {
  if (this._readableState.ranOut) {
    this._readableState.ranOut = false;
    flow(this);
  }
}


Readable.prototype.unpipe = function(dest) {
  var state = this._readableState;

  // if we're not piping anywhere, then do nothing.
  if (state.pipesCount === 0)
    return this;

  // just one destination.  most common case.
  if (state.pipesCount === 1) {
    // passed in one, but it's not the right one.
    if (dest && dest !== state.pipes)
      return this;

    if (!dest)
      dest = state.pipes;

    // got a match.
    state.pipes = null;
    state.pipesCount = 0;
    this.removeListener('readable', pipeOnReadable);
    state.flowing = false;
    if (dest)
      dest.emit('unpipe', this);
    return this;
  }

  // slow case. multiple pipe destinations.

  if (!dest) {
    // remove all.
    var dests = state.pipes;
    var len = state.pipesCount;
    state.pipes = null;
    state.pipesCount = 0;
    this.removeListener('readable', pipeOnReadable);
    state.flowing = false;

    for (var i = 0; i < len; i++)
      dests[i].emit('unpipe', this);
    return this;
  }

  // try to find the right one.
  var i = indexOf(state.pipes, dest);
  if (i === -1)
    return this;

  state.pipes.splice(i, 1);
  state.pipesCount -= 1;
  if (state.pipesCount === 1)
    state.pipes = state.pipes[0];

  dest.emit('unpipe', this);

  return this;
};

// set up data events if they are asked for
// Ensure readable listeners eventually get something
Readable.prototype.on = function(ev, fn) {
  var res = Stream.prototype.on.call(this, ev, fn);

  if (ev === 'data' && !this._readableState.flowing)
    emitDataEvents(this);

  if (ev === 'readable' && this.readable) {
    var state = this._readableState;
    if (!state.readableListening) {
      state.readableListening = true;
      state.emittedReadable = false;
      state.needReadable = true;
      if (!state.reading) {
        this.read(0);
      } else if (state.length) {
        emitReadable(this, state);
      }
    }
  }

  return res;
};
Readable.prototype.addListener = Readable.prototype.on;

// pause() and resume() are remnants of the legacy readable stream API
// If the user uses them, then switch into old mode.
Readable.prototype.resume = function() {
  emitDataEvents(this);
  this.read(0);
  this.emit('resume');
};

Readable.prototype.pause = function() {
  emitDataEvents(this, true);
  this.emit('pause');
};

function emitDataEvents(stream, startPaused) {
  var state = stream._readableState;

  if (state.flowing) {
    // https://github.com/isaacs/readable-stream/issues/16
    throw new Error('Cannot switch to old mode now.');
  }

  var paused = startPaused || false;
  var readable = false;

  // convert to an old-style stream.
  stream.readable = true;
  stream.pipe = Stream.prototype.pipe;
  stream.on = stream.addListener = Stream.prototype.on;

  stream.on('readable', function() {
    readable = true;

    var c;
    while (!paused && (null !== (c = stream.read())))
      stream.emit('data', c);

    if (c === null) {
      readable = false;
      stream._readableState.needReadable = true;
    }
  });

  stream.pause = function() {
    paused = true;
    this.emit('pause');
  };

  stream.resume = function() {
    paused = false;
    if (readable)
      process.nextTick(function() {
        stream.emit('readable');
      });
    else
      this.read(0);
    this.emit('resume');
  };

  // now make it start, just in case it hadn't already.
  stream.emit('readable');
}

// wrap an old-style stream as the async data source.
// This is *not* part of the readable stream interface.
// It is an ugly unfortunate mess of history.
Readable.prototype.wrap = function(stream) {
  var state = this._readableState;
  var paused = false;

  var self = this;
  stream.on('end', function() {
    if (state.decoder && !state.ended) {
      var chunk = state.decoder.end();
      if (chunk && chunk.length)
        self.push(chunk);
    }

    self.push(null);
  });

  stream.on('data', function(chunk) {
    if (state.decoder)
      chunk = state.decoder.write(chunk);

    // don't skip over falsy values in objectMode
    //if (state.objectMode && util.isNullOrUndefined(chunk))
    if (state.objectMode && (chunk === null || chunk === undefined))
      return;
    else if (!state.objectMode && (!chunk || !chunk.length))
      return;

    var ret = self.push(chunk);
    if (!ret) {
      paused = true;
      stream.pause();
    }
  });

  // proxy all the other methods.
  // important when wrapping filters and duplexes.
  for (var i in stream) {
    if (typeof stream[i] === 'function' &&
        typeof this[i] === 'undefined') {
      this[i] = function(method) { return function() {
        return stream[method].apply(stream, arguments);
      }}(i);
    }
  }

  // proxy certain important events.
  var events = ['error', 'close', 'destroy', 'pause', 'resume'];
  forEach(events, function(ev) {
    stream.on(ev, self.emit.bind(self, ev));
  });

  // when we try to consume some more bytes, simply unpause the
  // underlying stream.
  self._read = function(n) {
    if (paused) {
      paused = false;
      stream.resume();
    }
  };

  return self;
};



// exposed for testing purposes only.
Readable._fromList = fromList;

// Pluck off n bytes from an array of buffers.
// Length is the combined lengths of all the buffers in the list.
function fromList(n, state) {
  var list = state.buffer;
  var length = state.length;
  var stringMode = !!state.decoder;
  var objectMode = !!state.objectMode;
  var ret;

  // nothing in the list, definitely empty.
  if (list.length === 0)
    return null;

  if (length === 0)
    ret = null;
  else if (objectMode)
    ret = list.shift();
  else if (!n || n >= length) {
    // read it all, truncate the array.
    if (stringMode)
      ret = list.join('');
    else
      ret = Buffer.concat(list, length);
    list.length = 0;
  } else {
    // read just some of it.
    if (n < list[0].length) {
      // just take a part of the first list item.
      // slice is the same for buffers and strings.
      var buf = list[0];
      ret = buf.slice(0, n);
      list[0] = buf.slice(n);
    } else if (n === list[0].length) {
      // first list is a perfect match
      ret = list.shift();
    } else {
      // complex case.
      // we have enough to cover it, but it spans past the first buffer.
      if (stringMode)
        ret = '';
      else
        ret = new Buffer(n);

      var c = 0;
      for (var i = 0, l = list.length; i < l && c < n; i++) {
        var buf = list[0];
        var cpy = Math.min(n - c, buf.length);

        if (stringMode)
          ret += buf.slice(0, cpy);
        else
          buf.copy(ret, c, 0, cpy);

        if (cpy < buf.length)
          list[0] = buf.slice(cpy);
        else
          list.shift();

        c += cpy;
      }
    }
  }

  return ret;
}

function endReadable(stream) {
  var state = stream._readableState;

  // If we get here before consuming all the bytes, then that is a
  // bug in node.  Should never happen.
  if (state.length > 0)
    throw new Error('endReadable called on non-empty stream');

  if (!state.endEmitted && state.calledRead) {
    state.ended = true;
    process.nextTick(function() {
      // Check that we didn't get one last unshift.
      if (!state.endEmitted && state.length === 0) {
        state.endEmitted = true;
        stream.readable = false;
        stream.emit('end');
      }
    });
  }
}

function forEach (xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}

function indexOf (xs, x) {
  for (var i = 0, l = xs.length; i < l; i++) {
    if (xs[i] === x) return i;
  }
  return -1;
}

}).call(this,require('_process'))
},{"_process":113,"buffer":105,"core-util-is":6,"events":107,"inherits":28,"isarray":29,"stream":125,"string_decoder/":80}],87:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.


// a transform stream is a readable/writable stream where you do
// something with the data.  Sometimes it's called a "filter",
// but that's not a great name for it, since that implies a thing where
// some bits pass through, and others are simply ignored.  (That would
// be a valid example of a transform, of course.)
//
// While the output is causally related to the input, it's not a
// necessarily symmetric or synchronous transformation.  For example,
// a zlib stream might take multiple plain-text writes(), and then
// emit a single compressed chunk some time in the future.
//
// Here's how this works:
//
// The Transform stream has all the aspects of the readable and writable
// stream classes.  When you write(chunk), that calls _write(chunk,cb)
// internally, and returns false if there's a lot of pending writes
// buffered up.  When you call read(), that calls _read(n) until
// there's enough pending readable data buffered up.
//
// In a transform stream, the written data is placed in a buffer.  When
// _read(n) is called, it transforms the queued up data, calling the
// buffered _write cb's as it consumes chunks.  If consuming a single
// written chunk would result in multiple output chunks, then the first
// outputted bit calls the readcb, and subsequent chunks just go into
// the read buffer, and will cause it to emit 'readable' if necessary.
//
// This way, back-pressure is actually determined by the reading side,
// since _read has to be called to start processing a new chunk.  However,
// a pathological inflate type of transform can cause excessive buffering
// here.  For example, imagine a stream where every byte of input is
// interpreted as an integer from 0-255, and then results in that many
// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
// 1kb of data being output.  In this case, you could write a very small
// amount of input, and end up with a very large amount of output.  In
// such a pathological inflating mechanism, there'd be no way to tell
// the system to stop doing the transform.  A single 4MB write could
// cause the system to run out of memory.
//
// However, even in such a pathological case, only a single written chunk
// would be consumed, and then the rest would wait (un-transformed) until
// the results of the previous transformed chunk were consumed.

module.exports = Transform;

var Duplex = require('./_stream_duplex');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

util.inherits(Transform, Duplex);


function TransformState(options, stream) {
  this.afterTransform = function(er, data) {
    return afterTransform(stream, er, data);
  };

  this.needTransform = false;
  this.transforming = false;
  this.writecb = null;
  this.writechunk = null;
}

function afterTransform(stream, er, data) {
  var ts = stream._transformState;
  ts.transforming = false;

  var cb = ts.writecb;

  if (!cb)
    return stream.emit('error', new Error('no writecb in Transform class'));

  ts.writechunk = null;
  ts.writecb = null;

  if (data !== null && data !== undefined)
    stream.push(data);

  if (cb)
    cb(er);

  var rs = stream._readableState;
  rs.reading = false;
  if (rs.needReadable || rs.length < rs.highWaterMark) {
    stream._read(rs.highWaterMark);
  }
}


function Transform(options) {
  if (!(this instanceof Transform))
    return new Transform(options);

  Duplex.call(this, options);

  var ts = this._transformState = new TransformState(options, this);

  // when the writable side finishes, then flush out anything remaining.
  var stream = this;

  // start out asking for a readable event once data is transformed.
  this._readableState.needReadable = true;

  // we have implemented the _read method, and done the other things
  // that Readable wants before the first _read call, so unset the
  // sync guard flag.
  this._readableState.sync = false;

  this.once('finish', function() {
    if ('function' === typeof this._flush)
      this._flush(function(er) {
        done(stream, er);
      });
    else
      done(stream);
  });
}

Transform.prototype.push = function(chunk, encoding) {
  this._transformState.needTransform = false;
  return Duplex.prototype.push.call(this, chunk, encoding);
};

// This is the part where you do stuff!
// override this function in implementation classes.
// 'chunk' is an input chunk.
//
// Call `push(newChunk)` to pass along transformed output
// to the readable side.  You may call 'push' zero or more times.
//
// Call `cb(err)` when you are done with this chunk.  If you pass
// an error, then that'll put the hurt on the whole operation.  If you
// never call cb(), then you'll never get another chunk.
Transform.prototype._transform = function(chunk, encoding, cb) {
  throw new Error('not implemented');
};

Transform.prototype._write = function(chunk, encoding, cb) {
  var ts = this._transformState;
  ts.writecb = cb;
  ts.writechunk = chunk;
  ts.writeencoding = encoding;
  if (!ts.transforming) {
    var rs = this._readableState;
    if (ts.needTransform ||
        rs.needReadable ||
        rs.length < rs.highWaterMark)
      this._read(rs.highWaterMark);
  }
};

// Doesn't matter what the args are here.
// _transform does all the work.
// That we got here means that the readable side wants more data.
Transform.prototype._read = function(n) {
  var ts = this._transformState;

  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
    ts.transforming = true;
    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
  } else {
    // mark that we need a transform, so that any data that comes in
    // will get processed, now that we've asked for it.
    ts.needTransform = true;
  }
};


function done(stream, er) {
  if (er)
    return stream.emit('error', er);

  // if there's nothing in the write buffer, then that means
  // that nothing more will ever be provided
  var ws = stream._writableState;
  var rs = stream._readableState;
  var ts = stream._transformState;

  if (ws.length)
    throw new Error('calling transform done when ws.length != 0');

  if (ts.transforming)
    throw new Error('calling transform done when still transforming');

  return stream.push(null);
}

},{"./_stream_duplex":84,"core-util-is":6,"inherits":28}],88:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// A bit simpler than readable streams.
// Implement an async ._write(chunk, cb), and it'll handle all
// the drain event emission and buffering.

module.exports = Writable;

/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Writable.WritableState = WritableState;


/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var Stream = require('stream');

util.inherits(Writable, Stream);

function WriteReq(chunk, encoding, cb) {
  this.chunk = chunk;
  this.encoding = encoding;
  this.callback = cb;
}

function WritableState(options, stream) {
  options = options || {};

  // the point at which write() starts returning false
  // Note: 0 is a valid value, means that we always return false if
  // the entire buffer is not flushed immediately on write()
  var hwm = options.highWaterMark;
  this.highWaterMark = (hwm || hwm === 0) ? hwm : 16 * 1024;

  // object stream flag to indicate whether or not this stream
  // contains buffers or objects.
  this.objectMode = !!options.objectMode;

  // cast to ints.
  this.highWaterMark = ~~this.highWaterMark;

  this.needDrain = false;
  // at the start of calling end()
  this.ending = false;
  // when end() has been called, and returned
  this.ended = false;
  // when 'finish' is emitted
  this.finished = false;

  // should we decode strings into buffers before passing to _write?
  // this is here so that some node-core streams can optimize string
  // handling at a lower level.
  var noDecode = options.decodeStrings === false;
  this.decodeStrings = !noDecode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // not an actual buffer we keep track of, but a measurement
  // of how much we're waiting to get pushed to some underlying
  // socket or file.
  this.length = 0;

  // a flag to see when we're in the middle of a write.
  this.writing = false;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, becuase any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // a flag to know if we're processing previously buffered items, which
  // may call the _write() callback in the same tick, so that we don't
  // end up in an overlapped onwrite situation.
  this.bufferProcessing = false;

  // the callback that's passed to _write(chunk,cb)
  this.onwrite = function(er) {
    onwrite(stream, er);
  };

  // the callback that the user supplies to write(chunk,encoding,cb)
  this.writecb = null;

  // the amount that is being written when _write is called.
  this.writelen = 0;

  this.buffer = [];

  // True if the error was already emitted and should not be thrown again
  this.errorEmitted = false;
}

function Writable(options) {
  var Duplex = require('./_stream_duplex');

  // Writable ctor is applied to Duplexes, though they're not
  // instanceof Writable, they're instanceof Readable.
  if (!(this instanceof Writable) && !(this instanceof Duplex))
    return new Writable(options);

  this._writableState = new WritableState(options, this);

  // legacy.
  this.writable = true;

  Stream.call(this);
}

// Otherwise people can pipe Writable streams, which is just wrong.
Writable.prototype.pipe = function() {
  this.emit('error', new Error('Cannot pipe. Not readable.'));
};


function writeAfterEnd(stream, state, cb) {
  var er = new Error('write after end');
  // TODO: defer error events consistently everywhere, not just the cb
  stream.emit('error', er);
  process.nextTick(function() {
    cb(er);
  });
}

// If we get something that is not a buffer, string, null, or undefined,
// and we're not in objectMode, then that's an error.
// Otherwise stream chunks are all considered to be of length=1, and the
// watermarks determine how many objects to keep in the buffer, rather than
// how many bytes or characters.
function validChunk(stream, state, chunk, cb) {
  var valid = true;
  if (!Buffer.isBuffer(chunk) &&
      'string' !== typeof chunk &&
      chunk !== null &&
      chunk !== undefined &&
      !state.objectMode) {
    var er = new TypeError('Invalid non-string/buffer chunk');
    stream.emit('error', er);
    process.nextTick(function() {
      cb(er);
    });
    valid = false;
  }
  return valid;
}

Writable.prototype.write = function(chunk, encoding, cb) {
  var state = this._writableState;
  var ret = false;

  if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (Buffer.isBuffer(chunk))
    encoding = 'buffer';
  else if (!encoding)
    encoding = state.defaultEncoding;

  if (typeof cb !== 'function')
    cb = function() {};

  if (state.ended)
    writeAfterEnd(this, state, cb);
  else if (validChunk(this, state, chunk, cb))
    ret = writeOrBuffer(this, state, chunk, encoding, cb);

  return ret;
};

function decodeChunk(state, chunk, encoding) {
  if (!state.objectMode &&
      state.decodeStrings !== false &&
      typeof chunk === 'string') {
    chunk = new Buffer(chunk, encoding);
  }
  return chunk;
}

// if we're already writing something, then just put this
// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, cb) {
  chunk = decodeChunk(state, chunk, encoding);
  if (Buffer.isBuffer(chunk))
    encoding = 'buffer';
  var len = state.objectMode ? 1 : chunk.length;

  state.length += len;

  var ret = state.length < state.highWaterMark;
  // we must ensure that previous needDrain will not be reset to false.
  if (!ret)
    state.needDrain = true;

  if (state.writing)
    state.buffer.push(new WriteReq(chunk, encoding, cb));
  else
    doWrite(stream, state, len, chunk, encoding, cb);

  return ret;
}

function doWrite(stream, state, len, chunk, encoding, cb) {
  state.writelen = len;
  state.writecb = cb;
  state.writing = true;
  state.sync = true;
  stream._write(chunk, encoding, state.onwrite);
  state.sync = false;
}

function onwriteError(stream, state, sync, er, cb) {
  if (sync)
    process.nextTick(function() {
      cb(er);
    });
  else
    cb(er);

  stream._writableState.errorEmitted = true;
  stream.emit('error', er);
}

function onwriteStateUpdate(state) {
  state.writing = false;
  state.writecb = null;
  state.length -= state.writelen;
  state.writelen = 0;
}

function onwrite(stream, er) {
  var state = stream._writableState;
  var sync = state.sync;
  var cb = state.writecb;

  onwriteStateUpdate(state);

  if (er)
    onwriteError(stream, state, sync, er, cb);
  else {
    // Check if we're actually ready to finish, but don't emit yet
    var finished = needFinish(stream, state);

    if (!finished && !state.bufferProcessing && state.buffer.length)
      clearBuffer(stream, state);

    if (sync) {
      process.nextTick(function() {
        afterWrite(stream, state, finished, cb);
      });
    } else {
      afterWrite(stream, state, finished, cb);
    }
  }
}

function afterWrite(stream, state, finished, cb) {
  if (!finished)
    onwriteDrain(stream, state);
  cb();
  if (finished)
    finishMaybe(stream, state);
}

// Must force callback to be called on nextTick, so that we don't
// emit 'drain' before the write() consumer gets the 'false' return
// value, and has a chance to attach a 'drain' listener.
function onwriteDrain(stream, state) {
  if (state.length === 0 && state.needDrain) {
    state.needDrain = false;
    stream.emit('drain');
  }
}


// if there's something in the buffer waiting, then process it
function clearBuffer(stream, state) {
  state.bufferProcessing = true;

  for (var c = 0; c < state.buffer.length; c++) {
    var entry = state.buffer[c];
    var chunk = entry.chunk;
    var encoding = entry.encoding;
    var cb = entry.callback;
    var len = state.objectMode ? 1 : chunk.length;

    doWrite(stream, state, len, chunk, encoding, cb);

    // if we didn't call the onwrite immediately, then
    // it means that we need to wait until it does.
    // also, that means that the chunk and cb are currently
    // being processed, so move the buffer counter past them.
    if (state.writing) {
      c++;
      break;
    }
  }

  state.bufferProcessing = false;
  if (c < state.buffer.length)
    state.buffer = state.buffer.slice(c);
  else
    state.buffer.length = 0;
}

Writable.prototype._write = function(chunk, encoding, cb) {
  cb(new Error('not implemented'));
};

Writable.prototype.end = function(chunk, encoding, cb) {
  var state = this._writableState;

  if (typeof chunk === 'function') {
    cb = chunk;
    chunk = null;
    encoding = null;
  } else if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (typeof chunk !== 'undefined' && chunk !== null)
    this.write(chunk, encoding);

  // ignore unnecessary end() calls.
  if (!state.ending && !state.finished)
    endWritable(this, state, cb);
};


function needFinish(stream, state) {
  return (state.ending &&
          state.length === 0 &&
          !state.finished &&
          !state.writing);
}

function finishMaybe(stream, state) {
  var need = needFinish(stream, state);
  if (need) {
    state.finished = true;
    stream.emit('finish');
  }
  return need;
}

function endWritable(stream, state, cb) {
  state.ending = true;
  finishMaybe(stream, state);
  if (cb) {
    if (state.finished)
      process.nextTick(cb);
    else
      stream.once('finish', cb);
  }
  state.ended = true;
}

}).call(this,require('_process'))
},{"./_stream_duplex":84,"_process":113,"buffer":105,"core-util-is":6,"inherits":28,"stream":125}],89:[function(require,module,exports){
var Stream = require('stream'); // hack to fix a circular dependency issue when used with browserify
exports = module.exports = require('./lib/_stream_readable.js');
exports.Stream = Stream;
exports.Readable = exports;
exports.Writable = require('./lib/_stream_writable.js');
exports.Duplex = require('./lib/_stream_duplex.js');
exports.Transform = require('./lib/_stream_transform.js');
exports.PassThrough = require('./lib/_stream_passthrough.js');

},{"./lib/_stream_duplex.js":84,"./lib/_stream_passthrough.js":85,"./lib/_stream_readable.js":86,"./lib/_stream_transform.js":87,"./lib/_stream_writable.js":88,"stream":125}],90:[function(require,module,exports){
var toString = {}.toString;

module.exports = Array.isArray || function (arr) {
  return toString.call(arr) == '[object Array]';
};

},{}],91:[function(require,module,exports){
// a duplex stream is just a stream that is both readable and writable.
// Since JS doesn't have multiple prototypal inheritance, this class
// prototypally inherits from Readable, and then parasitically from
// Writable.

'use strict';

/*<replacement>*/

var objectKeys = Object.keys || function (obj) {
  var keys = [];
  for (var key in obj) {
    keys.push(key);
  }return keys;
};
/*</replacement>*/

module.exports = Duplex;

/*<replacement>*/
var processNextTick = require('process-nextick-args');
/*</replacement>*/

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var Readable = require('./_stream_readable');
var Writable = require('./_stream_writable');

util.inherits(Duplex, Readable);

var keys = objectKeys(Writable.prototype);
for (var v = 0; v < keys.length; v++) {
  var method = keys[v];
  if (!Duplex.prototype[method]) Duplex.prototype[method] = Writable.prototype[method];
}

function Duplex(options) {
  if (!(this instanceof Duplex)) return new Duplex(options);

  Readable.call(this, options);
  Writable.call(this, options);

  if (options && options.readable === false) this.readable = false;

  if (options && options.writable === false) this.writable = false;

  this.allowHalfOpen = true;
  if (options && options.allowHalfOpen === false) this.allowHalfOpen = false;

  this.once('end', onend);
}

// the no-half-open enforcer
function onend() {
  // if we allow half-open state, or if the writable side ended,
  // then we're ok.
  if (this.allowHalfOpen || this._writableState.ended) return;

  // no more data can be written.
  // But allow more writes to happen in this tick.
  processNextTick(onEndNT, this);
}

function onEndNT(self) {
  self.end();
}

function forEach(xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}
},{"./_stream_readable":92,"./_stream_writable":94,"core-util-is":6,"inherits":28,"process-nextick-args":70}],92:[function(require,module,exports){
(function (process){
'use strict';

module.exports = Readable;

/*<replacement>*/
var processNextTick = require('process-nextick-args');
/*</replacement>*/

/*<replacement>*/
var isArray = require('isarray');
/*</replacement>*/

/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Readable.ReadableState = ReadableState;

var EE = require('events');

/*<replacement>*/
var EElistenerCount = function (emitter, type) {
  return emitter.listeners(type).length;
};
/*</replacement>*/

/*<replacement>*/
var Stream;
(function () {
  try {
    Stream = require('st' + 'ream');
  } catch (_) {} finally {
    if (!Stream) Stream = require('events').EventEmitter;
  }
})();
/*</replacement>*/

var Buffer = require('buffer').Buffer;

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

/*<replacement>*/
var debugUtil = require('util');
var debug = undefined;
if (debugUtil && debugUtil.debuglog) {
  debug = debugUtil.debuglog('stream');
} else {
  debug = function () {};
}
/*</replacement>*/

var StringDecoder;

util.inherits(Readable, Stream);

var Duplex;
function ReadableState(options, stream) {
  Duplex = Duplex || require('./_stream_duplex');

  options = options || {};

  // object stream flag. Used to make read(n) ignore n and to
  // make all the buffer merging and length checks go away
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex) this.objectMode = this.objectMode || !!options.readableObjectMode;

  // the point at which it stops calling _read() to fill the buffer
  // Note: 0 is a valid value, means "don't call _read preemptively ever"
  var hwm = options.highWaterMark;
  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = hwm || hwm === 0 ? hwm : defaultHwm;

  // cast to ints.
  this.highWaterMark = ~ ~this.highWaterMark;

  this.buffer = [];
  this.length = 0;
  this.pipes = null;
  this.pipesCount = 0;
  this.flowing = null;
  this.ended = false;
  this.endEmitted = false;
  this.reading = false;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // whenever we return null, then we set a flag to say
  // that we're awaiting a 'readable' event emission.
  this.needReadable = false;
  this.emittedReadable = false;
  this.readableListening = false;
  this.resumeScheduled = false;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // when piping, we only care about 'readable' events that happen
  // after read()ing all the bytes and not getting any pushback.
  this.ranOut = false;

  // the number of writers that are awaiting a drain event in .pipe()s
  this.awaitDrain = 0;

  // if true, a maybeReadMore has been scheduled
  this.readingMore = false;

  this.decoder = null;
  this.encoding = null;
  if (options.encoding) {
    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
    this.decoder = new StringDecoder(options.encoding);
    this.encoding = options.encoding;
  }
}

var Duplex;
function Readable(options) {
  Duplex = Duplex || require('./_stream_duplex');

  if (!(this instanceof Readable)) return new Readable(options);

  this._readableState = new ReadableState(options, this);

  // legacy
  this.readable = true;

  if (options && typeof options.read === 'function') this._read = options.read;

  Stream.call(this);
}

// Manually shove something into the read() buffer.
// This returns true if the highWaterMark has not been hit yet,
// similar to how Writable.write() returns true if you should
// write() some more.
Readable.prototype.push = function (chunk, encoding) {
  var state = this._readableState;

  if (!state.objectMode && typeof chunk === 'string') {
    encoding = encoding || state.defaultEncoding;
    if (encoding !== state.encoding) {
      chunk = new Buffer(chunk, encoding);
      encoding = '';
    }
  }

  return readableAddChunk(this, state, chunk, encoding, false);
};

// Unshift should *always* be something directly out of read()
Readable.prototype.unshift = function (chunk) {
  var state = this._readableState;
  return readableAddChunk(this, state, chunk, '', true);
};

Readable.prototype.isPaused = function () {
  return this._readableState.flowing === false;
};

function readableAddChunk(stream, state, chunk, encoding, addToFront) {
  var er = chunkInvalid(state, chunk);
  if (er) {
    stream.emit('error', er);
  } else if (chunk === null) {
    state.reading = false;
    onEofChunk(stream, state);
  } else if (state.objectMode || chunk && chunk.length > 0) {
    if (state.ended && !addToFront) {
      var e = new Error('stream.push() after EOF');
      stream.emit('error', e);
    } else if (state.endEmitted && addToFront) {
      var e = new Error('stream.unshift() after end event');
      stream.emit('error', e);
    } else {
      var skipAdd;
      if (state.decoder && !addToFront && !encoding) {
        chunk = state.decoder.write(chunk);
        skipAdd = !state.objectMode && chunk.length === 0;
      }

      if (!addToFront) state.reading = false;

      // Don't add to the buffer if we've decoded to an empty string chunk and
      // we're not in object mode
      if (!skipAdd) {
        // if we want the data now, just emit it.
        if (state.flowing && state.length === 0 && !state.sync) {
          stream.emit('data', chunk);
          stream.read(0);
        } else {
          // update the buffer info.
          state.length += state.objectMode ? 1 : chunk.length;
          if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);

          if (state.needReadable) emitReadable(stream);
        }
      }

      maybeReadMore(stream, state);
    }
  } else if (!addToFront) {
    state.reading = false;
  }

  return needMoreData(state);
}

// if it's past the high water mark, we can push in some more.
// Also, if we have no data yet, we can stand some
// more bytes.  This is to work around cases where hwm=0,
// such as the repl.  Also, if the push() triggered a
// readable event, and the user called read(largeNumber) such that
// needReadable was set, then we ought to push more, so that another
// 'readable' event will be triggered.
function needMoreData(state) {
  return !state.ended && (state.needReadable || state.length < state.highWaterMark || state.length === 0);
}

// backwards compatibility.
Readable.prototype.setEncoding = function (enc) {
  if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
  this._readableState.decoder = new StringDecoder(enc);
  this._readableState.encoding = enc;
  return this;
};

// Don't raise the hwm > 8MB
var MAX_HWM = 0x800000;
function computeNewHighWaterMark(n) {
  if (n >= MAX_HWM) {
    n = MAX_HWM;
  } else {
    // Get the next highest power of 2
    n--;
    n |= n >>> 1;
    n |= n >>> 2;
    n |= n >>> 4;
    n |= n >>> 8;
    n |= n >>> 16;
    n++;
  }
  return n;
}

function howMuchToRead(n, state) {
  if (state.length === 0 && state.ended) return 0;

  if (state.objectMode) return n === 0 ? 0 : 1;

  if (n === null || isNaN(n)) {
    // only flow one buffer at a time
    if (state.flowing && state.buffer.length) return state.buffer[0].length;else return state.length;
  }

  if (n <= 0) return 0;

  // If we're asking for more than the target buffer level,
  // then raise the water mark.  Bump up to the next highest
  // power of 2, to prevent increasing it excessively in tiny
  // amounts.
  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);

  // don't have that much.  return null, unless we've ended.
  if (n > state.length) {
    if (!state.ended) {
      state.needReadable = true;
      return 0;
    } else {
      return state.length;
    }
  }

  return n;
}

// you can override either this method, or the async _read(n) below.
Readable.prototype.read = function (n) {
  debug('read', n);
  var state = this._readableState;
  var nOrig = n;

  if (typeof n !== 'number' || n > 0) state.emittedReadable = false;

  // if we're doing read(0) to trigger a readable event, but we
  // already have a bunch of data in the buffer, then just trigger
  // the 'readable' event and move on.
  if (n === 0 && state.needReadable && (state.length >= state.highWaterMark || state.ended)) {
    debug('read: emitReadable', state.length, state.ended);
    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
    return null;
  }

  n = howMuchToRead(n, state);

  // if we've ended, and we're now clear, then finish it up.
  if (n === 0 && state.ended) {
    if (state.length === 0) endReadable(this);
    return null;
  }

  // All the actual chunk generation logic needs to be
  // *below* the call to _read.  The reason is that in certain
  // synthetic stream cases, such as passthrough streams, _read
  // may be a completely synchronous operation which may change
  // the state of the read buffer, providing enough data when
  // before there was *not* enough.
  //
  // So, the steps are:
  // 1. Figure out what the state of things will be after we do
  // a read from the buffer.
  //
  // 2. If that resulting state will trigger a _read, then call _read.
  // Note that this may be asynchronous, or synchronous.  Yes, it is
  // deeply ugly to write APIs this way, but that still doesn't mean
  // that the Readable class should behave improperly, as streams are
  // designed to be sync/async agnostic.
  // Take note if the _read call is sync or async (ie, if the read call
  // has returned yet), so that we know whether or not it's safe to emit
  // 'readable' etc.
  //
  // 3. Actually pull the requested chunks out of the buffer and return.

  // if we need a readable event, then we need to do some reading.
  var doRead = state.needReadable;
  debug('need readable', doRead);

  // if we currently have less than the highWaterMark, then also read some
  if (state.length === 0 || state.length - n < state.highWaterMark) {
    doRead = true;
    debug('length less than watermark', doRead);
  }

  // however, if we've ended, then there's no point, and if we're already
  // reading, then it's unnecessary.
  if (state.ended || state.reading) {
    doRead = false;
    debug('reading or ended', doRead);
  }

  if (doRead) {
    debug('do read');
    state.reading = true;
    state.sync = true;
    // if the length is currently zero, then we *need* a readable event.
    if (state.length === 0) state.needReadable = true;
    // call internal read method
    this._read(state.highWaterMark);
    state.sync = false;
  }

  // If _read pushed data synchronously, then `reading` will be false,
  // and we need to re-evaluate how much data we can return to the user.
  if (doRead && !state.reading) n = howMuchToRead(nOrig, state);

  var ret;
  if (n > 0) ret = fromList(n, state);else ret = null;

  if (ret === null) {
    state.needReadable = true;
    n = 0;
  }

  state.length -= n;

  // If we have nothing in the buffer, then we want to know
  // as soon as we *do* get something into the buffer.
  if (state.length === 0 && !state.ended) state.needReadable = true;

  // If we tried to read() past the EOF, then emit end on the next tick.
  if (nOrig !== n && state.ended && state.length === 0) endReadable(this);

  if (ret !== null) this.emit('data', ret);

  return ret;
};

function chunkInvalid(state, chunk) {
  var er = null;
  if (!Buffer.isBuffer(chunk) && typeof chunk !== 'string' && chunk !== null && chunk !== undefined && !state.objectMode) {
    er = new TypeError('Invalid non-string/buffer chunk');
  }
  return er;
}

function onEofChunk(stream, state) {
  if (state.ended) return;
  if (state.decoder) {
    var chunk = state.decoder.end();
    if (chunk && chunk.length) {
      state.buffer.push(chunk);
      state.length += state.objectMode ? 1 : chunk.length;
    }
  }
  state.ended = true;

  // emit 'readable' now to make sure it gets picked up.
  emitReadable(stream);
}

// Don't emit readable right away in sync mode, because this can trigger
// another read() call => stack overflow.  This way, it might trigger
// a nextTick recursion warning, but that's not so bad.
function emitReadable(stream) {
  var state = stream._readableState;
  state.needReadable = false;
  if (!state.emittedReadable) {
    debug('emitReadable', state.flowing);
    state.emittedReadable = true;
    if (state.sync) processNextTick(emitReadable_, stream);else emitReadable_(stream);
  }
}

function emitReadable_(stream) {
  debug('emit readable');
  stream.emit('readable');
  flow(stream);
}

// at this point, the user has presumably seen the 'readable' event,
// and called read() to consume some data.  that may have triggered
// in turn another _read(n) call, in which case reading = true if
// it's in progress.
// However, if we're not ended, or reading, and the length < hwm,
// then go ahead and try to read some more preemptively.
function maybeReadMore(stream, state) {
  if (!state.readingMore) {
    state.readingMore = true;
    processNextTick(maybeReadMore_, stream, state);
  }
}

function maybeReadMore_(stream, state) {
  var len = state.length;
  while (!state.reading && !state.flowing && !state.ended && state.length < state.highWaterMark) {
    debug('maybeReadMore read 0');
    stream.read(0);
    if (len === state.length)
      // didn't get any data, stop spinning.
      break;else len = state.length;
  }
  state.readingMore = false;
}

// abstract method.  to be overridden in specific implementation classes.
// call cb(er, data) where data is <= n in length.
// for virtual (non-string, non-buffer) streams, "length" is somewhat
// arbitrary, and perhaps not very meaningful.
Readable.prototype._read = function (n) {
  this.emit('error', new Error('not implemented'));
};

Readable.prototype.pipe = function (dest, pipeOpts) {
  var src = this;
  var state = this._readableState;

  switch (state.pipesCount) {
    case 0:
      state.pipes = dest;
      break;
    case 1:
      state.pipes = [state.pipes, dest];
      break;
    default:
      state.pipes.push(dest);
      break;
  }
  state.pipesCount += 1;
  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);

  var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;

  var endFn = doEnd ? onend : cleanup;
  if (state.endEmitted) processNextTick(endFn);else src.once('end', endFn);

  dest.on('unpipe', onunpipe);
  function onunpipe(readable) {
    debug('onunpipe');
    if (readable === src) {
      cleanup();
    }
  }

  function onend() {
    debug('onend');
    dest.end();
  }

  // when the dest drains, it reduces the awaitDrain counter
  // on the source.  This would be more elegant with a .once()
  // handler in flow(), but adding and removing repeatedly is
  // too slow.
  var ondrain = pipeOnDrain(src);
  dest.on('drain', ondrain);

  var cleanedUp = false;
  function cleanup() {
    debug('cleanup');
    // cleanup event handlers once the pipe is broken
    dest.removeListener('close', onclose);
    dest.removeListener('finish', onfinish);
    dest.removeListener('drain', ondrain);
    dest.removeListener('error', onerror);
    dest.removeListener('unpipe', onunpipe);
    src.removeListener('end', onend);
    src.removeListener('end', cleanup);
    src.removeListener('data', ondata);

    cleanedUp = true;

    // if the reader is waiting for a drain event from this
    // specific writer, then it would cause it to never start
    // flowing again.
    // So, if this is awaiting a drain, then we just call it now.
    // If we don't know, then assume that we are waiting for one.
    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
  }

  src.on('data', ondata);
  function ondata(chunk) {
    debug('ondata');
    var ret = dest.write(chunk);
    if (false === ret) {
      // If the user unpiped during `dest.write()`, it is possible
      // to get stuck in a permanently paused state if that write
      // also returned false.
      if (state.pipesCount === 1 && state.pipes[0] === dest && src.listenerCount('data') === 1 && !cleanedUp) {
        debug('false write response, pause', src._readableState.awaitDrain);
        src._readableState.awaitDrain++;
      }
      src.pause();
    }
  }

  // if the dest has an error, then stop piping into it.
  // however, don't suppress the throwing behavior for this.
  function onerror(er) {
    debug('onerror', er);
    unpipe();
    dest.removeListener('error', onerror);
    if (EElistenerCount(dest, 'error') === 0) dest.emit('error', er);
  }
  // This is a brutally ugly hack to make sure that our error handler
  // is attached before any userland ones.  NEVER DO THIS.
  if (!dest._events || !dest._events.error) dest.on('error', onerror);else if (isArray(dest._events.error)) dest._events.error.unshift(onerror);else dest._events.error = [onerror, dest._events.error];

  // Both close and finish should trigger unpipe, but only once.
  function onclose() {
    dest.removeListener('finish', onfinish);
    unpipe();
  }
  dest.once('close', onclose);
  function onfinish() {
    debug('onfinish');
    dest.removeListener('close', onclose);
    unpipe();
  }
  dest.once('finish', onfinish);

  function unpipe() {
    debug('unpipe');
    src.unpipe(dest);
  }

  // tell the dest that it's being piped to
  dest.emit('pipe', src);

  // start the flow if it hasn't been started already.
  if (!state.flowing) {
    debug('pipe resume');
    src.resume();
  }

  return dest;
};

function pipeOnDrain(src) {
  return function () {
    var state = src._readableState;
    debug('pipeOnDrain', state.awaitDrain);
    if (state.awaitDrain) state.awaitDrain--;
    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
      state.flowing = true;
      flow(src);
    }
  };
}

Readable.prototype.unpipe = function (dest) {
  var state = this._readableState;

  // if we're not piping anywhere, then do nothing.
  if (state.pipesCount === 0) return this;

  // just one destination.  most common case.
  if (state.pipesCount === 1) {
    // passed in one, but it's not the right one.
    if (dest && dest !== state.pipes) return this;

    if (!dest) dest = state.pipes;

    // got a match.
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;
    if (dest) dest.emit('unpipe', this);
    return this;
  }

  // slow case. multiple pipe destinations.

  if (!dest) {
    // remove all.
    var dests = state.pipes;
    var len = state.pipesCount;
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;

    for (var _i = 0; _i < len; _i++) {
      dests[_i].emit('unpipe', this);
    }return this;
  }

  // try to find the right one.
  var i = indexOf(state.pipes, dest);
  if (i === -1) return this;

  state.pipes.splice(i, 1);
  state.pipesCount -= 1;
  if (state.pipesCount === 1) state.pipes = state.pipes[0];

  dest.emit('unpipe', this);

  return this;
};

// set up data events if they are asked for
// Ensure readable listeners eventually get something
Readable.prototype.on = function (ev, fn) {
  var res = Stream.prototype.on.call(this, ev, fn);

  // If listening to data, and it has not explicitly been paused,
  // then call resume to start the flow of data on the next tick.
  if (ev === 'data' && false !== this._readableState.flowing) {
    this.resume();
  }

  if (ev === 'readable' && !this._readableState.endEmitted) {
    var state = this._readableState;
    if (!state.readableListening) {
      state.readableListening = true;
      state.emittedReadable = false;
      state.needReadable = true;
      if (!state.reading) {
        processNextTick(nReadingNextTick, this);
      } else if (state.length) {
        emitReadable(this, state);
      }
    }
  }

  return res;
};
Readable.prototype.addListener = Readable.prototype.on;

function nReadingNextTick(self) {
  debug('readable nexttick read 0');
  self.read(0);
}

// pause() and resume() are remnants of the legacy readable stream API
// If the user uses them, then switch into old mode.
Readable.prototype.resume = function () {
  var state = this._readableState;
  if (!state.flowing) {
    debug('resume');
    state.flowing = true;
    resume(this, state);
  }
  return this;
};

function resume(stream, state) {
  if (!state.resumeScheduled) {
    state.resumeScheduled = true;
    processNextTick(resume_, stream, state);
  }
}

function resume_(stream, state) {
  if (!state.reading) {
    debug('resume read 0');
    stream.read(0);
  }

  state.resumeScheduled = false;
  stream.emit('resume');
  flow(stream);
  if (state.flowing && !state.reading) stream.read(0);
}

Readable.prototype.pause = function () {
  debug('call pause flowing=%j', this._readableState.flowing);
  if (false !== this._readableState.flowing) {
    debug('pause');
    this._readableState.flowing = false;
    this.emit('pause');
  }
  return this;
};

function flow(stream) {
  var state = stream._readableState;
  debug('flow', state.flowing);
  if (state.flowing) {
    do {
      var chunk = stream.read();
    } while (null !== chunk && state.flowing);
  }
}

// wrap an old-style stream as the async data source.
// This is *not* part of the readable stream interface.
// It is an ugly unfortunate mess of history.
Readable.prototype.wrap = function (stream) {
  var state = this._readableState;
  var paused = false;

  var self = this;
  stream.on('end', function () {
    debug('wrapped end');
    if (state.decoder && !state.ended) {
      var chunk = state.decoder.end();
      if (chunk && chunk.length) self.push(chunk);
    }

    self.push(null);
  });

  stream.on('data', function (chunk) {
    debug('wrapped data');
    if (state.decoder) chunk = state.decoder.write(chunk);

    // don't skip over falsy values in objectMode
    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;

    var ret = self.push(chunk);
    if (!ret) {
      paused = true;
      stream.pause();
    }
  });

  // proxy all the other methods.
  // important when wrapping filters and duplexes.
  for (var i in stream) {
    if (this[i] === undefined && typeof stream[i] === 'function') {
      this[i] = function (method) {
        return function () {
          return stream[method].apply(stream, arguments);
        };
      }(i);
    }
  }

  // proxy certain important events.
  var events = ['error', 'close', 'destroy', 'pause', 'resume'];
  forEach(events, function (ev) {
    stream.on(ev, self.emit.bind(self, ev));
  });

  // when we try to consume some more bytes, simply unpause the
  // underlying stream.
  self._read = function (n) {
    debug('wrapped _read', n);
    if (paused) {
      paused = false;
      stream.resume();
    }
  };

  return self;
};

// exposed for testing purposes only.
Readable._fromList = fromList;

// Pluck off n bytes from an array of buffers.
// Length is the combined lengths of all the buffers in the list.
function fromList(n, state) {
  var list = state.buffer;
  var length = state.length;
  var stringMode = !!state.decoder;
  var objectMode = !!state.objectMode;
  var ret;

  // nothing in the list, definitely empty.
  if (list.length === 0) return null;

  if (length === 0) ret = null;else if (objectMode) ret = list.shift();else if (!n || n >= length) {
    // read it all, truncate the array.
    if (stringMode) ret = list.join('');else if (list.length === 1) ret = list[0];else ret = Buffer.concat(list, length);
    list.length = 0;
  } else {
    // read just some of it.
    if (n < list[0].length) {
      // just take a part of the first list item.
      // slice is the same for buffers and strings.
      var buf = list[0];
      ret = buf.slice(0, n);
      list[0] = buf.slice(n);
    } else if (n === list[0].length) {
      // first list is a perfect match
      ret = list.shift();
    } else {
      // complex case.
      // we have enough to cover it, but it spans past the first buffer.
      if (stringMode) ret = '';else ret = new Buffer(n);

      var c = 0;
      for (var i = 0, l = list.length; i < l && c < n; i++) {
        var buf = list[0];
        var cpy = Math.min(n - c, buf.length);

        if (stringMode) ret += buf.slice(0, cpy);else buf.copy(ret, c, 0, cpy);

        if (cpy < buf.length) list[0] = buf.slice(cpy);else list.shift();

        c += cpy;
      }
    }
  }

  return ret;
}

function endReadable(stream) {
  var state = stream._readableState;

  // If we get here before consuming all the bytes, then that is a
  // bug in node.  Should never happen.
  if (state.length > 0) throw new Error('endReadable called on non-empty stream');

  if (!state.endEmitted) {
    state.ended = true;
    processNextTick(endReadableNT, state, stream);
  }
}

function endReadableNT(state, stream) {
  // Check that we didn't get one last unshift.
  if (!state.endEmitted && state.length === 0) {
    state.endEmitted = true;
    stream.readable = false;
    stream.emit('end');
  }
}

function forEach(xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}

function indexOf(xs, x) {
  for (var i = 0, l = xs.length; i < l; i++) {
    if (xs[i] === x) return i;
  }
  return -1;
}
}).call(this,require('_process'))
},{"./_stream_duplex":91,"_process":113,"buffer":105,"core-util-is":6,"events":107,"inherits":28,"isarray":90,"process-nextick-args":70,"string_decoder/":80,"util":103}],93:[function(require,module,exports){
// a transform stream is a readable/writable stream where you do
// something with the data.  Sometimes it's called a "filter",
// but that's not a great name for it, since that implies a thing where
// some bits pass through, and others are simply ignored.  (That would
// be a valid example of a transform, of course.)
//
// While the output is causally related to the input, it's not a
// necessarily symmetric or synchronous transformation.  For example,
// a zlib stream might take multiple plain-text writes(), and then
// emit a single compressed chunk some time in the future.
//
// Here's how this works:
//
// The Transform stream has all the aspects of the readable and writable
// stream classes.  When you write(chunk), that calls _write(chunk,cb)
// internally, and returns false if there's a lot of pending writes
// buffered up.  When you call read(), that calls _read(n) until
// there's enough pending readable data buffered up.
//
// In a transform stream, the written data is placed in a buffer.  When
// _read(n) is called, it transforms the queued up data, calling the
// buffered _write cb's as it consumes chunks.  If consuming a single
// written chunk would result in multiple output chunks, then the first
// outputted bit calls the readcb, and subsequent chunks just go into
// the read buffer, and will cause it to emit 'readable' if necessary.
//
// This way, back-pressure is actually determined by the reading side,
// since _read has to be called to start processing a new chunk.  However,
// a pathological inflate type of transform can cause excessive buffering
// here.  For example, imagine a stream where every byte of input is
// interpreted as an integer from 0-255, and then results in that many
// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
// 1kb of data being output.  In this case, you could write a very small
// amount of input, and end up with a very large amount of output.  In
// such a pathological inflating mechanism, there'd be no way to tell
// the system to stop doing the transform.  A single 4MB write could
// cause the system to run out of memory.
//
// However, even in such a pathological case, only a single written chunk
// would be consumed, and then the rest would wait (un-transformed) until
// the results of the previous transformed chunk were consumed.

'use strict';

module.exports = Transform;

var Duplex = require('./_stream_duplex');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

util.inherits(Transform, Duplex);

function TransformState(stream) {
  this.afterTransform = function (er, data) {
    return afterTransform(stream, er, data);
  };

  this.needTransform = false;
  this.transforming = false;
  this.writecb = null;
  this.writechunk = null;
  this.writeencoding = null;
}

function afterTransform(stream, er, data) {
  var ts = stream._transformState;
  ts.transforming = false;

  var cb = ts.writecb;

  if (!cb) return stream.emit('error', new Error('no writecb in Transform class'));

  ts.writechunk = null;
  ts.writecb = null;

  if (data !== null && data !== undefined) stream.push(data);

  cb(er);

  var rs = stream._readableState;
  rs.reading = false;
  if (rs.needReadable || rs.length < rs.highWaterMark) {
    stream._read(rs.highWaterMark);
  }
}

function Transform(options) {
  if (!(this instanceof Transform)) return new Transform(options);

  Duplex.call(this, options);

  this._transformState = new TransformState(this);

  // when the writable side finishes, then flush out anything remaining.
  var stream = this;

  // start out asking for a readable event once data is transformed.
  this._readableState.needReadable = true;

  // we have implemented the _read method, and done the other things
  // that Readable wants before the first _read call, so unset the
  // sync guard flag.
  this._readableState.sync = false;

  if (options) {
    if (typeof options.transform === 'function') this._transform = options.transform;

    if (typeof options.flush === 'function') this._flush = options.flush;
  }

  this.once('prefinish', function () {
    if (typeof this._flush === 'function') this._flush(function (er) {
      done(stream, er);
    });else done(stream);
  });
}

Transform.prototype.push = function (chunk, encoding) {
  this._transformState.needTransform = false;
  return Duplex.prototype.push.call(this, chunk, encoding);
};

// This is the part where you do stuff!
// override this function in implementation classes.
// 'chunk' is an input chunk.
//
// Call `push(newChunk)` to pass along transformed output
// to the readable side.  You may call 'push' zero or more times.
//
// Call `cb(err)` when you are done with this chunk.  If you pass
// an error, then that'll put the hurt on the whole operation.  If you
// never call cb(), then you'll never get another chunk.
Transform.prototype._transform = function (chunk, encoding, cb) {
  throw new Error('not implemented');
};

Transform.prototype._write = function (chunk, encoding, cb) {
  var ts = this._transformState;
  ts.writecb = cb;
  ts.writechunk = chunk;
  ts.writeencoding = encoding;
  if (!ts.transforming) {
    var rs = this._readableState;
    if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
  }
};

// Doesn't matter what the args are here.
// _transform does all the work.
// That we got here means that the readable side wants more data.
Transform.prototype._read = function (n) {
  var ts = this._transformState;

  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
    ts.transforming = true;
    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
  } else {
    // mark that we need a transform, so that any data that comes in
    // will get processed, now that we've asked for it.
    ts.needTransform = true;
  }
};

function done(stream, er) {
  if (er) return stream.emit('error', er);

  // if there's nothing in the write buffer, then that means
  // that nothing more will ever be provided
  var ws = stream._writableState;
  var ts = stream._transformState;

  if (ws.length) throw new Error('calling transform done when ws.length != 0');

  if (ts.transforming) throw new Error('calling transform done when still transforming');

  return stream.push(null);
}
},{"./_stream_duplex":91,"core-util-is":6,"inherits":28}],94:[function(require,module,exports){
(function (process){
// A bit simpler than readable streams.
// Implement an async ._write(chunk, encoding, cb), and it'll handle all
// the drain event emission and buffering.

'use strict';

module.exports = Writable;

/*<replacement>*/
var processNextTick = require('process-nextick-args');
/*</replacement>*/

/*<replacement>*/
var asyncWrite = !process.browser && ['v0.10', 'v0.9.'].indexOf(process.version.slice(0, 5)) > -1 ? setImmediate : processNextTick;
/*</replacement>*/

/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Writable.WritableState = WritableState;

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

/*<replacement>*/
var internalUtil = {
  deprecate: require('util-deprecate')
};
/*</replacement>*/

/*<replacement>*/
var Stream;
(function () {
  try {
    Stream = require('st' + 'ream');
  } catch (_) {} finally {
    if (!Stream) Stream = require('events').EventEmitter;
  }
})();
/*</replacement>*/

var Buffer = require('buffer').Buffer;

util.inherits(Writable, Stream);

function nop() {}

function WriteReq(chunk, encoding, cb) {
  this.chunk = chunk;
  this.encoding = encoding;
  this.callback = cb;
  this.next = null;
}

var Duplex;
function WritableState(options, stream) {
  Duplex = Duplex || require('./_stream_duplex');

  options = options || {};

  // object stream flag to indicate whether or not this stream
  // contains buffers or objects.
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex) this.objectMode = this.objectMode || !!options.writableObjectMode;

  // the point at which write() starts returning false
  // Note: 0 is a valid value, means that we always return false if
  // the entire buffer is not flushed immediately on write()
  var hwm = options.highWaterMark;
  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = hwm || hwm === 0 ? hwm : defaultHwm;

  // cast to ints.
  this.highWaterMark = ~ ~this.highWaterMark;

  this.needDrain = false;
  // at the start of calling end()
  this.ending = false;
  // when end() has been called, and returned
  this.ended = false;
  // when 'finish' is emitted
  this.finished = false;

  // should we decode strings into buffers before passing to _write?
  // this is here so that some node-core streams can optimize string
  // handling at a lower level.
  var noDecode = options.decodeStrings === false;
  this.decodeStrings = !noDecode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // not an actual buffer we keep track of, but a measurement
  // of how much we're waiting to get pushed to some underlying
  // socket or file.
  this.length = 0;

  // a flag to see when we're in the middle of a write.
  this.writing = false;

  // when true all writes will be buffered until .uncork() call
  this.corked = 0;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // a flag to know if we're processing previously buffered items, which
  // may call the _write() callback in the same tick, so that we don't
  // end up in an overlapped onwrite situation.
  this.bufferProcessing = false;

  // the callback that's passed to _write(chunk,cb)
  this.onwrite = function (er) {
    onwrite(stream, er);
  };

  // the callback that the user supplies to write(chunk,encoding,cb)
  this.writecb = null;

  // the amount that is being written when _write is called.
  this.writelen = 0;

  this.bufferedRequest = null;
  this.lastBufferedRequest = null;

  // number of pending user-supplied write callbacks
  // this must be 0 before 'finish' can be emitted
  this.pendingcb = 0;

  // emit prefinish if the only thing we're waiting for is _write cbs
  // This is relevant for synchronous Transform streams
  this.prefinished = false;

  // True if the error was already emitted and should not be thrown again
  this.errorEmitted = false;

  // count buffered requests
  this.bufferedRequestCount = 0;

  // create the two objects needed to store the corked requests
  // they are not a linked list, as no new elements are inserted in there
  this.corkedRequestsFree = new CorkedRequest(this);
  this.corkedRequestsFree.next = new CorkedRequest(this);
}

WritableState.prototype.getBuffer = function writableStateGetBuffer() {
  var current = this.bufferedRequest;
  var out = [];
  while (current) {
    out.push(current);
    current = current.next;
  }
  return out;
};

(function () {
  try {
    Object.defineProperty(WritableState.prototype, 'buffer', {
      get: internalUtil.deprecate(function () {
        return this.getBuffer();
      }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.')
    });
  } catch (_) {}
})();

var Duplex;
function Writable(options) {
  Duplex = Duplex || require('./_stream_duplex');

  // Writable ctor is applied to Duplexes, though they're not
  // instanceof Writable, they're instanceof Readable.
  if (!(this instanceof Writable) && !(this instanceof Duplex)) return new Writable(options);

  this._writableState = new WritableState(options, this);

  // legacy.
  this.writable = true;

  if (options) {
    if (typeof options.write === 'function') this._write = options.write;

    if (typeof options.writev === 'function') this._writev = options.writev;
  }

  Stream.call(this);
}

// Otherwise people can pipe Writable streams, which is just wrong.
Writable.prototype.pipe = function () {
  this.emit('error', new Error('Cannot pipe. Not readable.'));
};

function writeAfterEnd(stream, cb) {
  var er = new Error('write after end');
  // TODO: defer error events consistently everywhere, not just the cb
  stream.emit('error', er);
  processNextTick(cb, er);
}

// If we get something that is not a buffer, string, null, or undefined,
// and we're not in objectMode, then that's an error.
// Otherwise stream chunks are all considered to be of length=1, and the
// watermarks determine how many objects to keep in the buffer, rather than
// how many bytes or characters.
function validChunk(stream, state, chunk, cb) {
  var valid = true;

  if (!Buffer.isBuffer(chunk) && typeof chunk !== 'string' && chunk !== null && chunk !== undefined && !state.objectMode) {
    var er = new TypeError('Invalid non-string/buffer chunk');
    stream.emit('error', er);
    processNextTick(cb, er);
    valid = false;
  }
  return valid;
}

Writable.prototype.write = function (chunk, encoding, cb) {
  var state = this._writableState;
  var ret = false;

  if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (Buffer.isBuffer(chunk)) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;

  if (typeof cb !== 'function') cb = nop;

  if (state.ended) writeAfterEnd(this, cb);else if (validChunk(this, state, chunk, cb)) {
    state.pendingcb++;
    ret = writeOrBuffer(this, state, chunk, encoding, cb);
  }

  return ret;
};

Writable.prototype.cork = function () {
  var state = this._writableState;

  state.corked++;
};

Writable.prototype.uncork = function () {
  var state = this._writableState;

  if (state.corked) {
    state.corked--;

    if (!state.writing && !state.corked && !state.finished && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
  }
};

Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
  // node::ParseEncoding() requires lower case.
  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new TypeError('Unknown encoding: ' + encoding);
  this._writableState.defaultEncoding = encoding;
};

function decodeChunk(state, chunk, encoding) {
  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
    chunk = new Buffer(chunk, encoding);
  }
  return chunk;
}

// if we're already writing something, then just put this
// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, cb) {
  chunk = decodeChunk(state, chunk, encoding);

  if (Buffer.isBuffer(chunk)) encoding = 'buffer';
  var len = state.objectMode ? 1 : chunk.length;

  state.length += len;

  var ret = state.length < state.highWaterMark;
  // we must ensure that previous needDrain will not be reset to false.
  if (!ret) state.needDrain = true;

  if (state.writing || state.corked) {
    var last = state.lastBufferedRequest;
    state.lastBufferedRequest = new WriteReq(chunk, encoding, cb);
    if (last) {
      last.next = state.lastBufferedRequest;
    } else {
      state.bufferedRequest = state.lastBufferedRequest;
    }
    state.bufferedRequestCount += 1;
  } else {
    doWrite(stream, state, false, len, chunk, encoding, cb);
  }

  return ret;
}

function doWrite(stream, state, writev, len, chunk, encoding, cb) {
  state.writelen = len;
  state.writecb = cb;
  state.writing = true;
  state.sync = true;
  if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
  state.sync = false;
}

function onwriteError(stream, state, sync, er, cb) {
  --state.pendingcb;
  if (sync) processNextTick(cb, er);else cb(er);

  stream._writableState.errorEmitted = true;
  stream.emit('error', er);
}

function onwriteStateUpdate(state) {
  state.writing = false;
  state.writecb = null;
  state.length -= state.writelen;
  state.writelen = 0;
}

function onwrite(stream, er) {
  var state = stream._writableState;
  var sync = state.sync;
  var cb = state.writecb;

  onwriteStateUpdate(state);

  if (er) onwriteError(stream, state, sync, er, cb);else {
    // Check if we're actually ready to finish, but don't emit yet
    var finished = needFinish(state);

    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
      clearBuffer(stream, state);
    }

    if (sync) {
      /*<replacement>*/
      asyncWrite(afterWrite, stream, state, finished, cb);
      /*</replacement>*/
    } else {
        afterWrite(stream, state, finished, cb);
      }
  }
}

function afterWrite(stream, state, finished, cb) {
  if (!finished) onwriteDrain(stream, state);
  state.pendingcb--;
  cb();
  finishMaybe(stream, state);
}

// Must force callback to be called on nextTick, so that we don't
// emit 'drain' before the write() consumer gets the 'false' return
// value, and has a chance to attach a 'drain' listener.
function onwriteDrain(stream, state) {
  if (state.length === 0 && state.needDrain) {
    state.needDrain = false;
    stream.emit('drain');
  }
}

// if there's something in the buffer waiting, then process it
function clearBuffer(stream, state) {
  state.bufferProcessing = true;
  var entry = state.bufferedRequest;

  if (stream._writev && entry && entry.next) {
    // Fast case, write everything using _writev()
    var l = state.bufferedRequestCount;
    var buffer = new Array(l);
    var holder = state.corkedRequestsFree;
    holder.entry = entry;

    var count = 0;
    while (entry) {
      buffer[count] = entry;
      entry = entry.next;
      count += 1;
    }

    doWrite(stream, state, true, state.length, buffer, '', holder.finish);

    // doWrite is always async, defer these to save a bit of time
    // as the hot path ends with doWrite
    state.pendingcb++;
    state.lastBufferedRequest = null;
    state.corkedRequestsFree = holder.next;
    holder.next = null;
  } else {
    // Slow case, write chunks one-by-one
    while (entry) {
      var chunk = entry.chunk;
      var encoding = entry.encoding;
      var cb = entry.callback;
      var len = state.objectMode ? 1 : chunk.length;

      doWrite(stream, state, false, len, chunk, encoding, cb);
      entry = entry.next;
      // if we didn't call the onwrite immediately, then
      // it means that we need to wait until it does.
      // also, that means that the chunk and cb are currently
      // being processed, so move the buffer counter past them.
      if (state.writing) {
        break;
      }
    }

    if (entry === null) state.lastBufferedRequest = null;
  }

  state.bufferedRequestCount = 0;
  state.bufferedRequest = entry;
  state.bufferProcessing = false;
}

Writable.prototype._write = function (chunk, encoding, cb) {
  cb(new Error('not implemented'));
};

Writable.prototype._writev = null;

Writable.prototype.end = function (chunk, encoding, cb) {
  var state = this._writableState;

  if (typeof chunk === 'function') {
    cb = chunk;
    chunk = null;
    encoding = null;
  } else if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding);

  // .end() fully uncorks
  if (state.corked) {
    state.corked = 1;
    this.uncork();
  }

  // ignore unnecessary end() calls.
  if (!state.ending && !state.finished) endWritable(this, state, cb);
};

function needFinish(state) {
  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
}

function prefinish(stream, state) {
  if (!state.prefinished) {
    state.prefinished = true;
    stream.emit('prefinish');
  }
}

function finishMaybe(stream, state) {
  var need = needFinish(state);
  if (need) {
    if (state.pendingcb === 0) {
      prefinish(stream, state);
      state.finished = true;
      stream.emit('finish');
    } else {
      prefinish(stream, state);
    }
  }
  return need;
}

function endWritable(stream, state, cb) {
  state.ending = true;
  finishMaybe(stream, state);
  if (cb) {
    if (state.finished) processNextTick(cb);else stream.once('finish', cb);
  }
  state.ended = true;
  stream.writable = false;
}

// It seems a linked list but it is not
// there will be only 2 of these for each stream
function CorkedRequest(state) {
  var _this = this;

  this.next = null;
  this.entry = null;

  this.finish = function (err) {
    var entry = _this.entry;
    _this.entry = null;
    while (entry) {
      var cb = entry.callback;
      state.pendingcb--;
      cb(err);
      entry = entry.next;
    }
    if (state.corkedRequestsFree) {
      state.corkedRequestsFree.next = _this;
    } else {
      state.corkedRequestsFree = _this;
    }
  };
}
}).call(this,require('_process'))
},{"./_stream_duplex":91,"_process":113,"buffer":105,"core-util-is":6,"events":107,"inherits":28,"process-nextick-args":70,"util-deprecate":99}],95:[function(require,module,exports){
module.exports = require("./lib/_stream_transform.js")

},{"./lib/_stream_transform.js":93}],96:[function(require,module,exports){
arguments[4][17][0].apply(exports,arguments)
},{"dup":17}],97:[function(require,module,exports){
(function (process){
var Transform = require('readable-stream/transform')
  , inherits  = require('util').inherits
  , xtend     = require('xtend')

function DestroyableTransform(opts) {
  Transform.call(this, opts)
  this._destroyed = false
}

inherits(DestroyableTransform, Transform)

DestroyableTransform.prototype.destroy = function(err) {
  if (this._destroyed) return
  this._destroyed = true
  
  var self = this
  process.nextTick(function() {
    if (err)
      self.emit('error', err)
    self.emit('close')
  })
}

// a noop _transform function
function noop (chunk, enc, callback) {
  callback(null, chunk)
}


// create a new export function, used by both the main export and
// the .ctor export, contains common logic for dealing with arguments
function through2 (construct) {
  return function (options, transform, flush) {
    if (typeof options == 'function') {
      flush     = transform
      transform = options
      options   = {}
    }

    if (typeof transform != 'function')
      transform = noop

    if (typeof flush != 'function')
      flush = null

    return construct(options, transform, flush)
  }
}


// main export, just make me a transform stream!
module.exports = through2(function (options, transform, flush) {
  var t2 = new DestroyableTransform(options)

  t2._transform = transform

  if (flush)
    t2._flush = flush

  return t2
})


// make me a reusable prototype that I can `new`, or implicitly `new`
// with a constructor call
module.exports.ctor = through2(function (options, transform, flush) {
  function Through2 (override) {
    if (!(this instanceof Through2))
      return new Through2(override)

    this.options = xtend(options, override)

    DestroyableTransform.call(this, this.options)
  }

  inherits(Through2, DestroyableTransform)

  Through2.prototype._transform = transform

  if (flush)
    Through2.prototype._flush = flush

  return Through2
})


module.exports.obj = through2(function (options, transform, flush) {
  var t2 = new DestroyableTransform(xtend({ objectMode: true, highWaterMark: 16 }, options))

  t2._transform = transform

  if (flush)
    t2._flush = flush

  return t2
})

}).call(this,require('_process'))
},{"_process":113,"readable-stream/transform":95,"util":129,"xtend":96}],98:[function(require,module,exports){
'use strict';

// Simple FIFO queue implementation to avoid having to do shift()
// on an array, which is slow.

function Queue() {
  this.length = 0;
}

Queue.prototype.push = function (item) {
  var node = {item: item};
  if (this.last) {
    this.last = this.last.next = node;
  } else {
    this.last = this.first = node;
  }
  this.length++;
};

Queue.prototype.shift = function () {
  var node = this.first;
  if (node) {
    this.first = node.next;
    if (!(--this.length)) {
      this.last = undefined;
    }
    return node.item;
  }
};

Queue.prototype.slice = function (start, end) {
  start = typeof start === 'undefined' ? 0 : start;
  end = typeof end === 'undefined' ? Infinity : end;

  var output = [];

  var i = 0;
  for (var node = this.first; node; node = node.next) {
    if (--end < 0) {
      break;
    } else if (++i > start) {
      output.push(node.item);
    }
  }
  return output;
}

module.exports = Queue;

},{}],99:[function(require,module,exports){
(function (global){

/**
 * Module exports.
 */

module.exports = deprecate;

/**
 * Mark that a method should not be used.
 * Returns a modified function which warns once by default.
 *
 * If `localStorage.noDeprecation = true` is set, then it is a no-op.
 *
 * If `localStorage.throwDeprecation = true` is set, then deprecated functions
 * will throw an Error when invoked.
 *
 * If `localStorage.traceDeprecation = true` is set, then deprecated functions
 * will invoke `console.trace()` instead of `console.error()`.
 *
 * @param {Function} fn - the function to deprecate
 * @param {String} msg - the string to print to the console when `fn` is invoked
 * @returns {Function} a new "deprecated" version of `fn`
 * @api public
 */

function deprecate (fn, msg) {
  if (config('noDeprecation')) {
    return fn;
  }

  var warned = false;
  function deprecated() {
    if (!warned) {
      if (config('throwDeprecation')) {
        throw new Error(msg);
      } else if (config('traceDeprecation')) {
        console.trace(msg);
      } else {
        console.warn(msg);
      }
      warned = true;
    }
    return fn.apply(this, arguments);
  }

  return deprecated;
}

/**
 * Checks `localStorage` for boolean values for the given `name`.
 *
 * @param {String} name
 * @returns {Boolean}
 * @api private
 */

function config (name) {
  // accessing global.localStorage can trigger a DOMException in sandboxed iframes
  try {
    if (!global.localStorage) return false;
  } catch (_) {
    return false;
  }
  var val = global.localStorage[name];
  if (null == val) return false;
  return String(val).toLowerCase() === 'true';
}

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{}],100:[function(require,module,exports){
'use strict';

/**
 * Stringify/parse functions that don't operate
 * recursively, so they avoid call stack exceeded
 * errors.
 */
exports.stringify = function stringify(input) {
  var queue = [];
  queue.push({obj: input});

  var res = '';
  var next, obj, prefix, val, i, arrayPrefix, keys, k, key, value, objPrefix;
  while ((next = queue.pop())) {
    obj = next.obj;
    prefix = next.prefix || '';
    val = next.val || '';
    res += prefix;
    if (val) {
      res += val;
    } else if (typeof obj !== 'object') {
      res += typeof obj === 'undefined' ? null : JSON.stringify(obj);
    } else if (obj === null) {
      res += 'null';
    } else if (Array.isArray(obj)) {
      queue.push({val: ']'});
      for (i = obj.length - 1; i >= 0; i--) {
        arrayPrefix = i === 0 ? '' : ',';
        queue.push({obj: obj[i], prefix: arrayPrefix});
      }
      queue.push({val: '['});
    } else { // object
      keys = [];
      for (k in obj) {
        if (obj.hasOwnProperty(k)) {
          keys.push(k);
        }
      }
      queue.push({val: '}'});
      for (i = keys.length - 1; i >= 0; i--) {
        key = keys[i];
        value = obj[key];
        objPrefix = (i > 0 ? ',' : '');
        objPrefix += JSON.stringify(key) + ':';
        queue.push({obj: value, prefix: objPrefix});
      }
      queue.push({val: '{'});
    }
  }
  return res;
};

// Convenience function for the parse function.
// This pop function is basically copied from
// pouchCollate.parseIndexableString
function pop(obj, stack, metaStack) {
  var lastMetaElement = metaStack[metaStack.length - 1];
  if (obj === lastMetaElement.element) {
    // popping a meta-element, e.g. an object whose value is another object
    metaStack.pop();
    lastMetaElement = metaStack[metaStack.length - 1];
  }
  var element = lastMetaElement.element;
  var lastElementIndex = lastMetaElement.index;
  if (Array.isArray(element)) {
    element.push(obj);
  } else if (lastElementIndex === stack.length - 2) { // obj with key+value
    var key = stack.pop();
    element[key] = obj;
  } else {
    stack.push(obj); // obj with key only
  }
}

exports.parse = function (str) {
  var stack = [];
  var metaStack = []; // stack for arrays and objects
  var i = 0;
  var collationIndex,parsedNum,numChar;
  var parsedString,lastCh,numConsecutiveSlashes,ch;
  var arrayElement, objElement;
  while (true) {
    collationIndex = str[i++];
    if (collationIndex === '}' ||
        collationIndex === ']' ||
        typeof collationIndex === 'undefined') {
      if (stack.length === 1) {
        return stack.pop();
      } else {
        pop(stack.pop(), stack, metaStack);
        continue;
      }
    }
    switch (collationIndex) {
      case ' ':
      case '\t':
      case '\n':
      case ':':
      case ',':
        break;
      case 'n':
        i += 3; // 'ull'
        pop(null, stack, metaStack);
        break;
      case 't':
        i += 3; // 'rue'
        pop(true, stack, metaStack);
        break;
      case 'f':
        i += 4; // 'alse'
        pop(false, stack, metaStack);
        break;
      case '0':
      case '1':
      case '2':
      case '3':
      case '4':
      case '5':
      case '6':
      case '7':
      case '8':
      case '9':
      case '-':
        parsedNum = '';
        i--;
        while (true) {
          numChar = str[i++];
          if (/[\d\.\-e\+]/.test(numChar)) {
            parsedNum += numChar;
          } else {
            i--;
            break;
          }
        }
        pop(parseFloat(parsedNum), stack, metaStack);
        break;
      case '"':
        parsedString = '';
        lastCh = void 0;
        numConsecutiveSlashes = 0;
        while (true) {
          ch = str[i++];
          if (ch !== '"' || (lastCh === '\\' &&
              numConsecutiveSlashes % 2 === 1)) {
            parsedString += ch;
            lastCh = ch;
            if (lastCh === '\\') {
              numConsecutiveSlashes++;
            } else {
              numConsecutiveSlashes = 0;
            }
          } else {
            break;
          }
        }
        pop(JSON.parse('"' + parsedString + '"'), stack, metaStack);
        break;
      case '[':
        arrayElement = { element: [], index: stack.length };
        stack.push(arrayElement.element);
        metaStack.push(arrayElement);
        break;
      case '{':
        objElement = { element: {}, index: stack.length };
        stack.push(objElement.element);
        metaStack.push(objElement);
        break;
      default:
        throw new Error(
          'unexpectedly reached end of input: ' + collationIndex);
    }
  }
};

},{}],101:[function(require,module,exports){
module.exports = extend

function extend() {
    var target = {}

    for (var i = 0; i < arguments.length; i++) {
        var source = arguments[i]

        for (var key in source) {
            if (source.hasOwnProperty(key)) {
                target[key] = source[key]
            }
        }
    }

    return target
}

},{}],102:[function(require,module,exports){
'use strict'

exports.toByteArray = toByteArray
exports.fromByteArray = fromByteArray

var lookup = []
var revLookup = []
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array

function init () {
  var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
  for (var i = 0, len = code.length; i < len; ++i) {
    lookup[i] = code[i]
    revLookup[code.charCodeAt(i)] = i
  }

  revLookup['-'.charCodeAt(0)] = 62
  revLookup['_'.charCodeAt(0)] = 63
}

init()

function toByteArray (b64) {
  var i, j, l, tmp, placeHolders, arr
  var len = b64.length

  if (len % 4 > 0) {
    throw new Error('Invalid string. Length must be a multiple of 4')
  }

  // the number of equal signs (place holders)
  // if there are two placeholders, than the two characters before it
  // represent one byte
  // if there is only one, then the three characters before it represent 2 bytes
  // this is just a cheap hack to not do indexOf twice
  placeHolders = b64[len - 2] === '=' ? 2 : b64[len - 1] === '=' ? 1 : 0

  // base64 is 4/3 + up to two characters of the original data
  arr = new Arr(len * 3 / 4 - placeHolders)

  // if there are placeholders, only get up to the last complete 4 chars
  l = placeHolders > 0 ? len - 4 : len

  var L = 0

  for (i = 0, j = 0; i < l; i += 4, j += 3) {
    tmp = (revLookup[b64.charCodeAt(i)] << 18) | (revLookup[b64.charCodeAt(i + 1)] << 12) | (revLookup[b64.charCodeAt(i + 2)] << 6) | revLookup[b64.charCodeAt(i + 3)]
    arr[L++] = (tmp >> 16) & 0xFF
    arr[L++] = (tmp >> 8) & 0xFF
    arr[L++] = tmp & 0xFF
  }

  if (placeHolders === 2) {
    tmp = (revLookup[b64.charCodeAt(i)] << 2) | (revLookup[b64.charCodeAt(i + 1)] >> 4)
    arr[L++] = tmp & 0xFF
  } else if (placeHolders === 1) {
    tmp = (revLookup[b64.charCodeAt(i)] << 10) | (revLookup[b64.charCodeAt(i + 1)] << 4) | (revLookup[b64.charCodeAt(i + 2)] >> 2)
    arr[L++] = (tmp >> 8) & 0xFF
    arr[L++] = tmp & 0xFF
  }

  return arr
}

function tripletToBase64 (num) {
  return lookup[num >> 18 & 0x3F] + lookup[num >> 12 & 0x3F] + lookup[num >> 6 & 0x3F] + lookup[num & 0x3F]
}

function encodeChunk (uint8, start, end) {
  var tmp
  var output = []
  for (var i = start; i < end; i += 3) {
    tmp = (uint8[i] << 16) + (uint8[i + 1] << 8) + (uint8[i + 2])
    output.push(tripletToBase64(tmp))
  }
  return output.join('')
}

function fromByteArray (uint8) {
  var tmp
  var len = uint8.length
  var extraBytes = len % 3 // if we have 1 byte left, pad 2 bytes
  var output = ''
  var parts = []
  var maxChunkLength = 16383 // must be multiple of 3

  // go through the array every three bytes, we'll deal with trailing stuff later
  for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
    parts.push(encodeChunk(uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)))
  }

  // pad the end with zeros, but make sure to not forget the extra bytes
  if (extraBytes === 1) {
    tmp = uint8[len - 1]
    output += lookup[tmp >> 2]
    output += lookup[(tmp << 4) & 0x3F]
    output += '=='
  } else if (extraBytes === 2) {
    tmp = (uint8[len - 2] << 8) + (uint8[len - 1])
    output += lookup[tmp >> 10]
    output += lookup[(tmp >> 4) & 0x3F]
    output += lookup[(tmp << 2) & 0x3F]
    output += '='
  }

  parts.push(output)

  return parts.join('')
}

},{}],103:[function(require,module,exports){

},{}],104:[function(require,module,exports){
(function (global){
'use strict';

var buffer = require('buffer');
var Buffer = buffer.Buffer;
var SlowBuffer = buffer.SlowBuffer;
var MAX_LEN = buffer.kMaxLength || 2147483647;
exports.alloc = function alloc(size, fill, encoding) {
  if (typeof Buffer.alloc === 'function') {
    return Buffer.alloc(size, fill, encoding);
  }
  if (typeof encoding === 'number') {
    throw new TypeError('encoding must not be number');
  }
  if (typeof size !== 'number') {
    throw new TypeError('size must be a number');
  }
  if (size > MAX_LEN) {
    throw new RangeError('size is too large');
  }
  var enc = encoding;
  var _fill = fill;
  if (_fill === undefined) {
    enc = undefined;
    _fill = 0;
  }
  var buf = new Buffer(size);
  if (typeof _fill === 'string') {
    var fillBuf = new Buffer(_fill, enc);
    var flen = fillBuf.length;
    var i = -1;
    while (++i < size) {
      buf[i] = fillBuf[i % flen];
    }
  } else {
    buf.fill(_fill);
  }
  return buf;
}
exports.allocUnsafe = function allocUnsafe(size) {
  if (typeof Buffer.allocUnsafe === 'function') {
    return Buffer.allocUnsafe(size);
  }
  if (typeof size !== 'number') {
    throw new TypeError('size must be a number');
  }
  if (size > MAX_LEN) {
    throw new RangeError('size is too large');
  }
  return new Buffer(size);
}
exports.from = function from(value, encodingOrOffset, length) {
  if (typeof Buffer.from === 'function' && (!global.Uint8Array || Uint8Array.from !== Buffer.from)) {
    return Buffer.from(value, encodingOrOffset, length);
  }
  if (typeof value === 'number') {
    throw new TypeError('"value" argument must not be a number');
  }
  if (typeof value === 'string') {
    return new Buffer(value, encodingOrOffset);
  }
  if (typeof ArrayBuffer !== 'undefined' && value instanceof ArrayBuffer) {
    var offset = encodingOrOffset;
    if (arguments.length === 1) {
      return new Buffer(value);
    }
    if (typeof offset === 'undefined') {
      offset = 0;
    }
    var len = length;
    if (typeof len === 'undefined') {
      len = value.byteLength - offset;
    }
    if (offset >= value.byteLength) {
      throw new RangeError('\'offset\' is out of bounds');
    }
    if (len > value.byteLength - offset) {
      throw new RangeError('\'length\' is out of bounds');
    }
    return new Buffer(value.slice(offset, offset + len));
  }
  if (Buffer.isBuffer(value)) {
    var out = new Buffer(value.length);
    value.copy(out, 0, 0, value.length);
    return out;
  }
  if (value) {
    if (Array.isArray(value) || (typeof ArrayBuffer !== 'undefined' && value.buffer instanceof ArrayBuffer) || 'length' in value) {
      return new Buffer(value);
    }
    if (value.type === 'Buffer' && Array.isArray(value.data)) {
      return new Buffer(value.data);
    }
  }

  throw new TypeError('First argument must be a string, Buffer, ' + 'ArrayBuffer, Array, or array-like object.');
}
exports.allocUnsafeSlow = function allocUnsafeSlow(size) {
  if (typeof Buffer.allocUnsafeSlow === 'function') {
    return Buffer.allocUnsafeSlow(size);
  }
  if (typeof size !== 'number') {
    throw new TypeError('size must be a number');
  }
  if (size >= MAX_LEN) {
    throw new RangeError('size is too large');
  }
  return new SlowBuffer(size);
}

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"buffer":105}],105:[function(require,module,exports){
(function (global){
/*!
 * The buffer module from node.js, for the browser.
 *
 * @author   Feross Aboukhadijeh <feross@feross.org> <http://feross.org>
 * @license  MIT
 */
/* eslint-disable no-proto */

'use strict'

var base64 = require('base64-js')
var ieee754 = require('ieee754')
var isArray = require('isarray')

exports.Buffer = Buffer
exports.SlowBuffer = SlowBuffer
exports.INSPECT_MAX_BYTES = 50

/**
 * If `Buffer.TYPED_ARRAY_SUPPORT`:
 *   === true    Use Uint8Array implementation (fastest)
 *   === false   Use Object implementation (most compatible, even IE6)
 *
 * Browsers that support typed arrays are IE 10+, Firefox 4+, Chrome 7+, Safari 5.1+,
 * Opera 11.6+, iOS 4.2+.
 *
 * Due to various browser bugs, sometimes the Object implementation will be used even
 * when the browser supports typed arrays.
 *
 * Note:
 *
 *   - Firefox 4-29 lacks support for adding new properties to `Uint8Array` instances,
 *     See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438.
 *
 *   - Chrome 9-10 is missing the `TypedArray.prototype.subarray` function.
 *
 *   - IE10 has a broken `TypedArray.prototype.subarray` function which returns arrays of
 *     incorrect length in some situations.

 * We detect these buggy browsers and set `Buffer.TYPED_ARRAY_SUPPORT` to `false` so they
 * get the Object implementation, which is slower but behaves correctly.
 */
Buffer.TYPED_ARRAY_SUPPORT = global.TYPED_ARRAY_SUPPORT !== undefined
  ? global.TYPED_ARRAY_SUPPORT
  : typedArraySupport()

/*
 * Export kMaxLength after typed array support is determined.
 */
exports.kMaxLength = kMaxLength()

function typedArraySupport () {
  try {
    var arr = new Uint8Array(1)
    arr.__proto__ = {__proto__: Uint8Array.prototype, foo: function () { return 42 }}
    return arr.foo() === 42 && // typed array instances can be augmented
        typeof arr.subarray === 'function' && // chrome 9-10 lack `subarray`
        arr.subarray(1, 1).byteLength === 0 // ie10 has broken `subarray`
  } catch (e) {
    return false
  }
}

function kMaxLength () {
  return Buffer.TYPED_ARRAY_SUPPORT
    ? 0x7fffffff
    : 0x3fffffff
}

function createBuffer (that, length) {
  if (kMaxLength() < length) {
    throw new RangeError('Invalid typed array length')
  }
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    // Return an augmented `Uint8Array` instance, for best performance
    that = new Uint8Array(length)
    that.__proto__ = Buffer.prototype
  } else {
    // Fallback: Return an object instance of the Buffer class
    if (that === null) {
      that = new Buffer(length)
    }
    that.length = length
  }

  return that
}

/**
 * The Buffer constructor returns instances of `Uint8Array` that have their
 * prototype changed to `Buffer.prototype`. Furthermore, `Buffer` is a subclass of
 * `Uint8Array`, so the returned instances will have all the node `Buffer` methods
 * and the `Uint8Array` methods. Square bracket notation works as expected -- it
 * returns a single octet.
 *
 * The `Uint8Array` prototype remains unmodified.
 */

function Buffer (arg, encodingOrOffset, length) {
  if (!Buffer.TYPED_ARRAY_SUPPORT && !(this instanceof Buffer)) {
    return new Buffer(arg, encodingOrOffset, length)
  }

  // Common case.
  if (typeof arg === 'number') {
    if (typeof encodingOrOffset === 'string') {
      throw new Error(
        'If encoding is specified then the first argument must be a string'
      )
    }
    return allocUnsafe(this, arg)
  }
  return from(this, arg, encodingOrOffset, length)
}

Buffer.poolSize = 8192 // not used by this implementation

// TODO: Legacy, not needed anymore. Remove in next major version.
Buffer._augment = function (arr) {
  arr.__proto__ = Buffer.prototype
  return arr
}

function from (that, value, encodingOrOffset, length) {
  if (typeof value === 'number') {
    throw new TypeError('"value" argument must not be a number')
  }

  if (typeof ArrayBuffer !== 'undefined' && value instanceof ArrayBuffer) {
    return fromArrayBuffer(that, value, encodingOrOffset, length)
  }

  if (typeof value === 'string') {
    return fromString(that, value, encodingOrOffset)
  }

  return fromObject(that, value)
}

/**
 * Functionally equivalent to Buffer(arg, encoding) but throws a TypeError
 * if value is a number.
 * Buffer.from(str[, encoding])
 * Buffer.from(array)
 * Buffer.from(buffer)
 * Buffer.from(arrayBuffer[, byteOffset[, length]])
 **/
Buffer.from = function (value, encodingOrOffset, length) {
  return from(null, value, encodingOrOffset, length)
}

if (Buffer.TYPED_ARRAY_SUPPORT) {
  Buffer.prototype.__proto__ = Uint8Array.prototype
  Buffer.__proto__ = Uint8Array
  if (typeof Symbol !== 'undefined' && Symbol.species &&
      Buffer[Symbol.species] === Buffer) {
    // Fix subarray() in ES2016. See: https://github.com/feross/buffer/pull/97
    Object.defineProperty(Buffer, Symbol.species, {
      value: null,
      configurable: true
    })
  }
}

function assertSize (size) {
  if (typeof size !== 'number') {
    throw new TypeError('"size" argument must be a number')
  } else if (size < 0) {
    throw new RangeError('"size" argument must not be negative')
  }
}

function alloc (that, size, fill, encoding) {
  assertSize(size)
  if (size <= 0) {
    return createBuffer(that, size)
  }
  if (fill !== undefined) {
    // Only pay attention to encoding if it's a string. This
    // prevents accidentally sending in a number that would
    // be interpretted as a start offset.
    return typeof encoding === 'string'
      ? createBuffer(that, size).fill(fill, encoding)
      : createBuffer(that, size).fill(fill)
  }
  return createBuffer(that, size)
}

/**
 * Creates a new filled Buffer instance.
 * alloc(size[, fill[, encoding]])
 **/
Buffer.alloc = function (size, fill, encoding) {
  return alloc(null, size, fill, encoding)
}

function allocUnsafe (that, size) {
  assertSize(size)
  that = createBuffer(that, size < 0 ? 0 : checked(size) | 0)
  if (!Buffer.TYPED_ARRAY_SUPPORT) {
    for (var i = 0; i < size; ++i) {
      that[i] = 0
    }
  }
  return that
}

/**
 * Equivalent to Buffer(num), by default creates a non-zero-filled Buffer instance.
 * */
Buffer.allocUnsafe = function (size) {
  return allocUnsafe(null, size)
}
/**
 * Equivalent to SlowBuffer(num), by default creates a non-zero-filled Buffer instance.
 */
Buffer.allocUnsafeSlow = function (size) {
  return allocUnsafe(null, size)
}

function fromString (that, string, encoding) {
  if (typeof encoding !== 'string' || encoding === '') {
    encoding = 'utf8'
  }

  if (!Buffer.isEncoding(encoding)) {
    throw new TypeError('"encoding" must be a valid string encoding')
  }

  var length = byteLength(string, encoding) | 0
  that = createBuffer(that, length)

  var actual = that.write(string, encoding)

  if (actual !== length) {
    // Writing a hex string, for example, that contains invalid characters will
    // cause everything after the first invalid character to be ignored. (e.g.
    // 'abxxcd' will be treated as 'ab')
    that = that.slice(0, actual)
  }

  return that
}

function fromArrayLike (that, array) {
  var length = array.length < 0 ? 0 : checked(array.length) | 0
  that = createBuffer(that, length)
  for (var i = 0; i < length; i += 1) {
    that[i] = array[i] & 255
  }
  return that
}

function fromArrayBuffer (that, array, byteOffset, length) {
  array.byteLength // this throws if `array` is not a valid ArrayBuffer

  if (byteOffset < 0 || array.byteLength < byteOffset) {
    throw new RangeError('\'offset\' is out of bounds')
  }

  if (array.byteLength < byteOffset + (length || 0)) {
    throw new RangeError('\'length\' is out of bounds')
  }

  if (byteOffset === undefined && length === undefined) {
    array = new Uint8Array(array)
  } else if (length === undefined) {
    array = new Uint8Array(array, byteOffset)
  } else {
    array = new Uint8Array(array, byteOffset, length)
  }

  if (Buffer.TYPED_ARRAY_SUPPORT) {
    // Return an augmented `Uint8Array` instance, for best performance
    that = array
    that.__proto__ = Buffer.prototype
  } else {
    // Fallback: Return an object instance of the Buffer class
    that = fromArrayLike(that, array)
  }
  return that
}

function fromObject (that, obj) {
  if (Buffer.isBuffer(obj)) {
    var len = checked(obj.length) | 0
    that = createBuffer(that, len)

    if (that.length === 0) {
      return that
    }

    obj.copy(that, 0, 0, len)
    return that
  }

  if (obj) {
    if ((typeof ArrayBuffer !== 'undefined' &&
        obj.buffer instanceof ArrayBuffer) || 'length' in obj) {
      if (typeof obj.length !== 'number' || isnan(obj.length)) {
        return createBuffer(that, 0)
      }
      return fromArrayLike(that, obj)
    }

    if (obj.type === 'Buffer' && isArray(obj.data)) {
      return fromArrayLike(that, obj.data)
    }
  }

  throw new TypeError('First argument must be a string, Buffer, ArrayBuffer, Array, or array-like object.')
}

function checked (length) {
  // Note: cannot use `length < kMaxLength()` here because that fails when
  // length is NaN (which is otherwise coerced to zero.)
  if (length >= kMaxLength()) {
    throw new RangeError('Attempt to allocate Buffer larger than maximum ' +
                         'size: 0x' + kMaxLength().toString(16) + ' bytes')
  }
  return length | 0
}

function SlowBuffer (length) {
  if (+length != length) { // eslint-disable-line eqeqeq
    length = 0
  }
  return Buffer.alloc(+length)
}

Buffer.isBuffer = function isBuffer (b) {
  return !!(b != null && b._isBuffer)
}

Buffer.compare = function compare (a, b) {
  if (!Buffer.isBuffer(a) || !Buffer.isBuffer(b)) {
    throw new TypeError('Arguments must be Buffers')
  }

  if (a === b) return 0

  var x = a.length
  var y = b.length

  for (var i = 0, len = Math.min(x, y); i < len; ++i) {
    if (a[i] !== b[i]) {
      x = a[i]
      y = b[i]
      break
    }
  }

  if (x < y) return -1
  if (y < x) return 1
  return 0
}

Buffer.isEncoding = function isEncoding (encoding) {
  switch (String(encoding).toLowerCase()) {
    case 'hex':
    case 'utf8':
    case 'utf-8':
    case 'ascii':
    case 'latin1':
    case 'binary':
    case 'base64':
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      return true
    default:
      return false
  }
}

Buffer.concat = function concat (list, length) {
  if (!isArray(list)) {
    throw new TypeError('"list" argument must be an Array of Buffers')
  }

  if (list.length === 0) {
    return Buffer.alloc(0)
  }

  var i
  if (length === undefined) {
    length = 0
    for (i = 0; i < list.length; ++i) {
      length += list[i].length
    }
  }

  var buffer = Buffer.allocUnsafe(length)
  var pos = 0
  for (i = 0; i < list.length; ++i) {
    var buf = list[i]
    if (!Buffer.isBuffer(buf)) {
      throw new TypeError('"list" argument must be an Array of Buffers')
    }
    buf.copy(buffer, pos)
    pos += buf.length
  }
  return buffer
}

function byteLength (string, encoding) {
  if (Buffer.isBuffer(string)) {
    return string.length
  }
  if (typeof ArrayBuffer !== 'undefined' && typeof ArrayBuffer.isView === 'function' &&
      (ArrayBuffer.isView(string) || string instanceof ArrayBuffer)) {
    return string.byteLength
  }
  if (typeof string !== 'string') {
    string = '' + string
  }

  var len = string.length
  if (len === 0) return 0

  // Use a for loop to avoid recursion
  var loweredCase = false
  for (;;) {
    switch (encoding) {
      case 'ascii':
      case 'latin1':
      case 'binary':
        return len
      case 'utf8':
      case 'utf-8':
      case undefined:
        return utf8ToBytes(string).length
      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return len * 2
      case 'hex':
        return len >>> 1
      case 'base64':
        return base64ToBytes(string).length
      default:
        if (loweredCase) return utf8ToBytes(string).length // assume utf8
        encoding = ('' + encoding).toLowerCase()
        loweredCase = true
    }
  }
}
Buffer.byteLength = byteLength

function slowToString (encoding, start, end) {
  var loweredCase = false

  // No need to verify that "this.length <= MAX_UINT32" since it's a read-only
  // property of a typed array.

  // This behaves neither like String nor Uint8Array in that we set start/end
  // to their upper/lower bounds if the value passed is out of range.
  // undefined is handled specially as per ECMA-262 6th Edition,
  // Section 13.3.3.7 Runtime Semantics: KeyedBindingInitialization.
  if (start === undefined || start < 0) {
    start = 0
  }
  // Return early if start > this.length. Done here to prevent potential uint32
  // coercion fail below.
  if (start > this.length) {
    return ''
  }

  if (end === undefined || end > this.length) {
    end = this.length
  }

  if (end <= 0) {
    return ''
  }

  // Force coersion to uint32. This will also coerce falsey/NaN values to 0.
  end >>>= 0
  start >>>= 0

  if (end <= start) {
    return ''
  }

  if (!encoding) encoding = 'utf8'

  while (true) {
    switch (encoding) {
      case 'hex':
        return hexSlice(this, start, end)

      case 'utf8':
      case 'utf-8':
        return utf8Slice(this, start, end)

      case 'ascii':
        return asciiSlice(this, start, end)

      case 'latin1':
      case 'binary':
        return latin1Slice(this, start, end)

      case 'base64':
        return base64Slice(this, start, end)

      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return utf16leSlice(this, start, end)

      default:
        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding)
        encoding = (encoding + '').toLowerCase()
        loweredCase = true
    }
  }
}

// The property is used by `Buffer.isBuffer` and `is-buffer` (in Safari 5-7) to detect
// Buffer instances.
Buffer.prototype._isBuffer = true

function swap (b, n, m) {
  var i = b[n]
  b[n] = b[m]
  b[m] = i
}

Buffer.prototype.swap16 = function swap16 () {
  var len = this.length
  if (len % 2 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 16-bits')
  }
  for (var i = 0; i < len; i += 2) {
    swap(this, i, i + 1)
  }
  return this
}

Buffer.prototype.swap32 = function swap32 () {
  var len = this.length
  if (len % 4 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 32-bits')
  }
  for (var i = 0; i < len; i += 4) {
    swap(this, i, i + 3)
    swap(this, i + 1, i + 2)
  }
  return this
}

Buffer.prototype.swap64 = function swap64 () {
  var len = this.length
  if (len % 8 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 64-bits')
  }
  for (var i = 0; i < len; i += 8) {
    swap(this, i, i + 7)
    swap(this, i + 1, i + 6)
    swap(this, i + 2, i + 5)
    swap(this, i + 3, i + 4)
  }
  return this
}

Buffer.prototype.toString = function toString () {
  var length = this.length | 0
  if (length === 0) return ''
  if (arguments.length === 0) return utf8Slice(this, 0, length)
  return slowToString.apply(this, arguments)
}

Buffer.prototype.equals = function equals (b) {
  if (!Buffer.isBuffer(b)) throw new TypeError('Argument must be a Buffer')
  if (this === b) return true
  return Buffer.compare(this, b) === 0
}

Buffer.prototype.inspect = function inspect () {
  var str = ''
  var max = exports.INSPECT_MAX_BYTES
  if (this.length > 0) {
    str = this.toString('hex', 0, max).match(/.{2}/g).join(' ')
    if (this.length > max) str += ' ... '
  }
  return '<Buffer ' + str + '>'
}

Buffer.prototype.compare = function compare (target, start, end, thisStart, thisEnd) {
  if (!Buffer.isBuffer(target)) {
    throw new TypeError('Argument must be a Buffer')
  }

  if (start === undefined) {
    start = 0
  }
  if (end === undefined) {
    end = target ? target.length : 0
  }
  if (thisStart === undefined) {
    thisStart = 0
  }
  if (thisEnd === undefined) {
    thisEnd = this.length
  }

  if (start < 0 || end > target.length || thisStart < 0 || thisEnd > this.length) {
    throw new RangeError('out of range index')
  }

  if (thisStart >= thisEnd && start >= end) {
    return 0
  }
  if (thisStart >= thisEnd) {
    return -1
  }
  if (start >= end) {
    return 1
  }

  start >>>= 0
  end >>>= 0
  thisStart >>>= 0
  thisEnd >>>= 0

  if (this === target) return 0

  var x = thisEnd - thisStart
  var y = end - start
  var len = Math.min(x, y)

  var thisCopy = this.slice(thisStart, thisEnd)
  var targetCopy = target.slice(start, end)

  for (var i = 0; i < len; ++i) {
    if (thisCopy[i] !== targetCopy[i]) {
      x = thisCopy[i]
      y = targetCopy[i]
      break
    }
  }

  if (x < y) return -1
  if (y < x) return 1
  return 0
}

// Finds either the first index of `val` in `buffer` at offset >= `byteOffset`,
// OR the last index of `val` in `buffer` at offset <= `byteOffset`.
//
// Arguments:
// - buffer - a Buffer to search
// - val - a string, Buffer, or number
// - byteOffset - an index into `buffer`; will be clamped to an int32
// - encoding - an optional encoding, relevant is val is a string
// - dir - true for indexOf, false for lastIndexOf
function bidirectionalIndexOf (buffer, val, byteOffset, encoding, dir) {
  // Empty buffer means no match
  if (buffer.length === 0) return -1

  // Normalize byteOffset
  if (typeof byteOffset === 'string') {
    encoding = byteOffset
    byteOffset = 0
  } else if (byteOffset > 0x7fffffff) {
    byteOffset = 0x7fffffff
  } else if (byteOffset < -0x80000000) {
    byteOffset = -0x80000000
  }
  byteOffset = +byteOffset  // Coerce to Number.
  if (isNaN(byteOffset)) {
    // byteOffset: it it's undefined, null, NaN, "foo", etc, search whole buffer
    byteOffset = dir ? 0 : (buffer.length - 1)
  }

  // Normalize byteOffset: negative offsets start from the end of the buffer
  if (byteOffset < 0) byteOffset = buffer.length + byteOffset
  if (byteOffset >= buffer.length) {
    if (dir) return -1
    else byteOffset = buffer.length - 1
  } else if (byteOffset < 0) {
    if (dir) byteOffset = 0
    else return -1
  }

  // Normalize val
  if (typeof val === 'string') {
    val = Buffer.from(val, encoding)
  }

  // Finally, search either indexOf (if dir is true) or lastIndexOf
  if (Buffer.isBuffer(val)) {
    // Special case: looking for empty string/buffer always fails
    if (val.length === 0) {
      return -1
    }
    return arrayIndexOf(buffer, val, byteOffset, encoding, dir)
  } else if (typeof val === 'number') {
    val = val & 0xFF // Search for a byte value [0-255]
    if (Buffer.TYPED_ARRAY_SUPPORT &&
        typeof Uint8Array.prototype.indexOf === 'function') {
      if (dir) {
        return Uint8Array.prototype.indexOf.call(buffer, val, byteOffset)
      } else {
        return Uint8Array.prototype.lastIndexOf.call(buffer, val, byteOffset)
      }
    }
    return arrayIndexOf(buffer, [ val ], byteOffset, encoding, dir)
  }

  throw new TypeError('val must be string, number or Buffer')
}

function arrayIndexOf (arr, val, byteOffset, encoding, dir) {
  var indexSize = 1
  var arrLength = arr.length
  var valLength = val.length

  if (encoding !== undefined) {
    encoding = String(encoding).toLowerCase()
    if (encoding === 'ucs2' || encoding === 'ucs-2' ||
        encoding === 'utf16le' || encoding === 'utf-16le') {
      if (arr.length < 2 || val.length < 2) {
        return -1
      }
      indexSize = 2
      arrLength /= 2
      valLength /= 2
      byteOffset /= 2
    }
  }

  function read (buf, i) {
    if (indexSize === 1) {
      return buf[i]
    } else {
      return buf.readUInt16BE(i * indexSize)
    }
  }

  var i
  if (dir) {
    var foundIndex = -1
    for (i = byteOffset; i < arrLength; i++) {
      if (read(arr, i) === read(val, foundIndex === -1 ? 0 : i - foundIndex)) {
        if (foundIndex === -1) foundIndex = i
        if (i - foundIndex + 1 === valLength) return foundIndex * indexSize
      } else {
        if (foundIndex !== -1) i -= i - foundIndex
        foundIndex = -1
      }
    }
  } else {
    if (byteOffset + valLength > arrLength) byteOffset = arrLength - valLength
    for (i = byteOffset; i >= 0; i--) {
      var found = true
      for (var j = 0; j < valLength; j++) {
        if (read(arr, i + j) !== read(val, j)) {
          found = false
          break
        }
      }
      if (found) return i
    }
  }

  return -1
}

Buffer.prototype.includes = function includes (val, byteOffset, encoding) {
  return this.indexOf(val, byteOffset, encoding) !== -1
}

Buffer.prototype.indexOf = function indexOf (val, byteOffset, encoding) {
  return bidirectionalIndexOf(this, val, byteOffset, encoding, true)
}

Buffer.prototype.lastIndexOf = function lastIndexOf (val, byteOffset, encoding) {
  return bidirectionalIndexOf(this, val, byteOffset, encoding, false)
}

function hexWrite (buf, string, offset, length) {
  offset = Number(offset) || 0
  var remaining = buf.length - offset
  if (!length) {
    length = remaining
  } else {
    length = Number(length)
    if (length > remaining) {
      length = remaining
    }
  }

  // must be an even number of digits
  var strLen = string.length
  if (strLen % 2 !== 0) throw new TypeError('Invalid hex string')

  if (length > strLen / 2) {
    length = strLen / 2
  }
  for (var i = 0; i < length; ++i) {
    var parsed = parseInt(string.substr(i * 2, 2), 16)
    if (isNaN(parsed)) return i
    buf[offset + i] = parsed
  }
  return i
}

function utf8Write (buf, string, offset, length) {
  return blitBuffer(utf8ToBytes(string, buf.length - offset), buf, offset, length)
}

function asciiWrite (buf, string, offset, length) {
  return blitBuffer(asciiToBytes(string), buf, offset, length)
}

function latin1Write (buf, string, offset, length) {
  return asciiWrite(buf, string, offset, length)
}

function base64Write (buf, string, offset, length) {
  return blitBuffer(base64ToBytes(string), buf, offset, length)
}

function ucs2Write (buf, string, offset, length) {
  return blitBuffer(utf16leToBytes(string, buf.length - offset), buf, offset, length)
}

Buffer.prototype.write = function write (string, offset, length, encoding) {
  // Buffer#write(string)
  if (offset === undefined) {
    encoding = 'utf8'
    length = this.length
    offset = 0
  // Buffer#write(string, encoding)
  } else if (length === undefined && typeof offset === 'string') {
    encoding = offset
    length = this.length
    offset = 0
  // Buffer#write(string, offset[, length][, encoding])
  } else if (isFinite(offset)) {
    offset = offset | 0
    if (isFinite(length)) {
      length = length | 0
      if (encoding === undefined) encoding = 'utf8'
    } else {
      encoding = length
      length = undefined
    }
  // legacy write(string, encoding, offset, length) - remove in v0.13
  } else {
    throw new Error(
      'Buffer.write(string, encoding, offset[, length]) is no longer supported'
    )
  }

  var remaining = this.length - offset
  if (length === undefined || length > remaining) length = remaining

  if ((string.length > 0 && (length < 0 || offset < 0)) || offset > this.length) {
    throw new RangeError('Attempt to write outside buffer bounds')
  }

  if (!encoding) encoding = 'utf8'

  var loweredCase = false
  for (;;) {
    switch (encoding) {
      case 'hex':
        return hexWrite(this, string, offset, length)

      case 'utf8':
      case 'utf-8':
        return utf8Write(this, string, offset, length)

      case 'ascii':
        return asciiWrite(this, string, offset, length)

      case 'latin1':
      case 'binary':
        return latin1Write(this, string, offset, length)

      case 'base64':
        // Warning: maxLength not taken into account in base64Write
        return base64Write(this, string, offset, length)

      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return ucs2Write(this, string, offset, length)

      default:
        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding)
        encoding = ('' + encoding).toLowerCase()
        loweredCase = true
    }
  }
}

Buffer.prototype.toJSON = function toJSON () {
  return {
    type: 'Buffer',
    data: Array.prototype.slice.call(this._arr || this, 0)
  }
}

function base64Slice (buf, start, end) {
  if (start === 0 && end === buf.length) {
    return base64.fromByteArray(buf)
  } else {
    return base64.fromByteArray(buf.slice(start, end))
  }
}

function utf8Slice (buf, start, end) {
  end = Math.min(buf.length, end)
  var res = []

  var i = start
  while (i < end) {
    var firstByte = buf[i]
    var codePoint = null
    var bytesPerSequence = (firstByte > 0xEF) ? 4
      : (firstByte > 0xDF) ? 3
      : (firstByte > 0xBF) ? 2
      : 1

    if (i + bytesPerSequence <= end) {
      var secondByte, thirdByte, fourthByte, tempCodePoint

      switch (bytesPerSequence) {
        case 1:
          if (firstByte < 0x80) {
            codePoint = firstByte
          }
          break
        case 2:
          secondByte = buf[i + 1]
          if ((secondByte & 0xC0) === 0x80) {
            tempCodePoint = (firstByte & 0x1F) << 0x6 | (secondByte & 0x3F)
            if (tempCodePoint > 0x7F) {
              codePoint = tempCodePoint
            }
          }
          break
        case 3:
          secondByte = buf[i + 1]
          thirdByte = buf[i + 2]
          if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80) {
            tempCodePoint = (firstByte & 0xF) << 0xC | (secondByte & 0x3F) << 0x6 | (thirdByte & 0x3F)
            if (tempCodePoint > 0x7FF && (tempCodePoint < 0xD800 || tempCodePoint > 0xDFFF)) {
              codePoint = tempCodePoint
            }
          }
          break
        case 4:
          secondByte = buf[i + 1]
          thirdByte = buf[i + 2]
          fourthByte = buf[i + 3]
          if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80 && (fourthByte & 0xC0) === 0x80) {
            tempCodePoint = (firstByte & 0xF) << 0x12 | (secondByte & 0x3F) << 0xC | (thirdByte & 0x3F) << 0x6 | (fourthByte & 0x3F)
            if (tempCodePoint > 0xFFFF && tempCodePoint < 0x110000) {
              codePoint = tempCodePoint
            }
          }
      }
    }

    if (codePoint === null) {
      // we did not generate a valid codePoint so insert a
      // replacement char (U+FFFD) and advance only 1 byte
      codePoint = 0xFFFD
      bytesPerSequence = 1
    } else if (codePoint > 0xFFFF) {
      // encode to utf16 (surrogate pair dance)
      codePoint -= 0x10000
      res.push(codePoint >>> 10 & 0x3FF | 0xD800)
      codePoint = 0xDC00 | codePoint & 0x3FF
    }

    res.push(codePoint)
    i += bytesPerSequence
  }

  return decodeCodePointsArray(res)
}

// Based on http://stackoverflow.com/a/22747272/680742, the browser with
// the lowest limit is Chrome, with 0x10000 args.
// We go 1 magnitude less, for safety
var MAX_ARGUMENTS_LENGTH = 0x1000

function decodeCodePointsArray (codePoints) {
  var len = codePoints.length
  if (len <= MAX_ARGUMENTS_LENGTH) {
    return String.fromCharCode.apply(String, codePoints) // avoid extra slice()
  }

  // Decode in chunks to avoid "call stack size exceeded".
  var res = ''
  var i = 0
  while (i < len) {
    res += String.fromCharCode.apply(
      String,
      codePoints.slice(i, i += MAX_ARGUMENTS_LENGTH)
    )
  }
  return res
}

function asciiSlice (buf, start, end) {
  var ret = ''
  end = Math.min(buf.length, end)

  for (var i = start; i < end; ++i) {
    ret += String.fromCharCode(buf[i] & 0x7F)
  }
  return ret
}

function latin1Slice (buf, start, end) {
  var ret = ''
  end = Math.min(buf.length, end)

  for (var i = start; i < end; ++i) {
    ret += String.fromCharCode(buf[i])
  }
  return ret
}

function hexSlice (buf, start, end) {
  var len = buf.length

  if (!start || start < 0) start = 0
  if (!end || end < 0 || end > len) end = len

  var out = ''
  for (var i = start; i < end; ++i) {
    out += toHex(buf[i])
  }
  return out
}

function utf16leSlice (buf, start, end) {
  var bytes = buf.slice(start, end)
  var res = ''
  for (var i = 0; i < bytes.length; i += 2) {
    res += String.fromCharCode(bytes[i] + bytes[i + 1] * 256)
  }
  return res
}

Buffer.prototype.slice = function slice (start, end) {
  var len = this.length
  start = ~~start
  end = end === undefined ? len : ~~end

  if (start < 0) {
    start += len
    if (start < 0) start = 0
  } else if (start > len) {
    start = len
  }

  if (end < 0) {
    end += len
    if (end < 0) end = 0
  } else if (end > len) {
    end = len
  }

  if (end < start) end = start

  var newBuf
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    newBuf = this.subarray(start, end)
    newBuf.__proto__ = Buffer.prototype
  } else {
    var sliceLen = end - start
    newBuf = new Buffer(sliceLen, undefined)
    for (var i = 0; i < sliceLen; ++i) {
      newBuf[i] = this[i + start]
    }
  }

  return newBuf
}

/*
 * Need to make sure that buffer isn't trying to write out of bounds.
 */
function checkOffset (offset, ext, length) {
  if ((offset % 1) !== 0 || offset < 0) throw new RangeError('offset is not uint')
  if (offset + ext > length) throw new RangeError('Trying to access beyond buffer length')
}

Buffer.prototype.readUIntLE = function readUIntLE (offset, byteLength, noAssert) {
  offset = offset | 0
  byteLength = byteLength | 0
  if (!noAssert) checkOffset(offset, byteLength, this.length)

  var val = this[offset]
  var mul = 1
  var i = 0
  while (++i < byteLength && (mul *= 0x100)) {
    val += this[offset + i] * mul
  }

  return val
}

Buffer.prototype.readUIntBE = function readUIntBE (offset, byteLength, noAssert) {
  offset = offset | 0
  byteLength = byteLength | 0
  if (!noAssert) {
    checkOffset(offset, byteLength, this.length)
  }

  var val = this[offset + --byteLength]
  var mul = 1
  while (byteLength > 0 && (mul *= 0x100)) {
    val += this[offset + --byteLength] * mul
  }

  return val
}

Buffer.prototype.readUInt8 = function readUInt8 (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 1, this.length)
  return this[offset]
}

Buffer.prototype.readUInt16LE = function readUInt16LE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 2, this.length)
  return this[offset] | (this[offset + 1] << 8)
}

Buffer.prototype.readUInt16BE = function readUInt16BE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 2, this.length)
  return (this[offset] << 8) | this[offset + 1]
}

Buffer.prototype.readUInt32LE = function readUInt32LE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)

  return ((this[offset]) |
      (this[offset + 1] << 8) |
      (this[offset + 2] << 16)) +
      (this[offset + 3] * 0x1000000)
}

Buffer.prototype.readUInt32BE = function readUInt32BE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)

  return (this[offset] * 0x1000000) +
    ((this[offset + 1] << 16) |
    (this[offset + 2] << 8) |
    this[offset + 3])
}

Buffer.prototype.readIntLE = function readIntLE (offset, byteLength, noAssert) {
  offset = offset | 0
  byteLength = byteLength | 0
  if (!noAssert) checkOffset(offset, byteLength, this.length)

  var val = this[offset]
  var mul = 1
  var i = 0
  while (++i < byteLength && (mul *= 0x100)) {
    val += this[offset + i] * mul
  }
  mul *= 0x80

  if (val >= mul) val -= Math.pow(2, 8 * byteLength)

  return val
}

Buffer.prototype.readIntBE = function readIntBE (offset, byteLength, noAssert) {
  offset = offset | 0
  byteLength = byteLength | 0
  if (!noAssert) checkOffset(offset, byteLength, this.length)

  var i = byteLength
  var mul = 1
  var val = this[offset + --i]
  while (i > 0 && (mul *= 0x100)) {
    val += this[offset + --i] * mul
  }
  mul *= 0x80

  if (val >= mul) val -= Math.pow(2, 8 * byteLength)

  return val
}

Buffer.prototype.readInt8 = function readInt8 (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 1, this.length)
  if (!(this[offset] & 0x80)) return (this[offset])
  return ((0xff - this[offset] + 1) * -1)
}

Buffer.prototype.readInt16LE = function readInt16LE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 2, this.length)
  var val = this[offset] | (this[offset + 1] << 8)
  return (val & 0x8000) ? val | 0xFFFF0000 : val
}

Buffer.prototype.readInt16BE = function readInt16BE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 2, this.length)
  var val = this[offset + 1] | (this[offset] << 8)
  return (val & 0x8000) ? val | 0xFFFF0000 : val
}

Buffer.prototype.readInt32LE = function readInt32LE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)

  return (this[offset]) |
    (this[offset + 1] << 8) |
    (this[offset + 2] << 16) |
    (this[offset + 3] << 24)
}

Buffer.prototype.readInt32BE = function readInt32BE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)

  return (this[offset] << 24) |
    (this[offset + 1] << 16) |
    (this[offset + 2] << 8) |
    (this[offset + 3])
}

Buffer.prototype.readFloatLE = function readFloatLE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)
  return ieee754.read(this, offset, true, 23, 4)
}

Buffer.prototype.readFloatBE = function readFloatBE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)
  return ieee754.read(this, offset, false, 23, 4)
}

Buffer.prototype.readDoubleLE = function readDoubleLE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 8, this.length)
  return ieee754.read(this, offset, true, 52, 8)
}

Buffer.prototype.readDoubleBE = function readDoubleBE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 8, this.length)
  return ieee754.read(this, offset, false, 52, 8)
}

function checkInt (buf, value, offset, ext, max, min) {
  if (!Buffer.isBuffer(buf)) throw new TypeError('"buffer" argument must be a Buffer instance')
  if (value > max || value < min) throw new RangeError('"value" argument is out of bounds')
  if (offset + ext > buf.length) throw new RangeError('Index out of range')
}

Buffer.prototype.writeUIntLE = function writeUIntLE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset | 0
  byteLength = byteLength | 0
  if (!noAssert) {
    var maxBytes = Math.pow(2, 8 * byteLength) - 1
    checkInt(this, value, offset, byteLength, maxBytes, 0)
  }

  var mul = 1
  var i = 0
  this[offset] = value & 0xFF
  while (++i < byteLength && (mul *= 0x100)) {
    this[offset + i] = (value / mul) & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeUIntBE = function writeUIntBE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset | 0
  byteLength = byteLength | 0
  if (!noAssert) {
    var maxBytes = Math.pow(2, 8 * byteLength) - 1
    checkInt(this, value, offset, byteLength, maxBytes, 0)
  }

  var i = byteLength - 1
  var mul = 1
  this[offset + i] = value & 0xFF
  while (--i >= 0 && (mul *= 0x100)) {
    this[offset + i] = (value / mul) & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeUInt8 = function writeUInt8 (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 1, 0xff, 0)
  if (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value)
  this[offset] = (value & 0xff)
  return offset + 1
}

function objectWriteUInt16 (buf, value, offset, littleEndian) {
  if (value < 0) value = 0xffff + value + 1
  for (var i = 0, j = Math.min(buf.length - offset, 2); i < j; ++i) {
    buf[offset + i] = (value & (0xff << (8 * (littleEndian ? i : 1 - i)))) >>>
      (littleEndian ? i : 1 - i) * 8
  }
}

Buffer.prototype.writeUInt16LE = function writeUInt16LE (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value & 0xff)
    this[offset + 1] = (value >>> 8)
  } else {
    objectWriteUInt16(this, value, offset, true)
  }
  return offset + 2
}

Buffer.prototype.writeUInt16BE = function writeUInt16BE (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 8)
    this[offset + 1] = (value & 0xff)
  } else {
    objectWriteUInt16(this, value, offset, false)
  }
  return offset + 2
}

function objectWriteUInt32 (buf, value, offset, littleEndian) {
  if (value < 0) value = 0xffffffff + value + 1
  for (var i = 0, j = Math.min(buf.length - offset, 4); i < j; ++i) {
    buf[offset + i] = (value >>> (littleEndian ? i : 3 - i) * 8) & 0xff
  }
}

Buffer.prototype.writeUInt32LE = function writeUInt32LE (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset + 3] = (value >>> 24)
    this[offset + 2] = (value >>> 16)
    this[offset + 1] = (value >>> 8)
    this[offset] = (value & 0xff)
  } else {
    objectWriteUInt32(this, value, offset, true)
  }
  return offset + 4
}

Buffer.prototype.writeUInt32BE = function writeUInt32BE (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 24)
    this[offset + 1] = (value >>> 16)
    this[offset + 2] = (value >>> 8)
    this[offset + 3] = (value & 0xff)
  } else {
    objectWriteUInt32(this, value, offset, false)
  }
  return offset + 4
}

Buffer.prototype.writeIntLE = function writeIntLE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) {
    var limit = Math.pow(2, 8 * byteLength - 1)

    checkInt(this, value, offset, byteLength, limit - 1, -limit)
  }

  var i = 0
  var mul = 1
  var sub = 0
  this[offset] = value & 0xFF
  while (++i < byteLength && (mul *= 0x100)) {
    if (value < 0 && sub === 0 && this[offset + i - 1] !== 0) {
      sub = 1
    }
    this[offset + i] = ((value / mul) >> 0) - sub & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeIntBE = function writeIntBE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) {
    var limit = Math.pow(2, 8 * byteLength - 1)

    checkInt(this, value, offset, byteLength, limit - 1, -limit)
  }

  var i = byteLength - 1
  var mul = 1
  var sub = 0
  this[offset + i] = value & 0xFF
  while (--i >= 0 && (mul *= 0x100)) {
    if (value < 0 && sub === 0 && this[offset + i + 1] !== 0) {
      sub = 1
    }
    this[offset + i] = ((value / mul) >> 0) - sub & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeInt8 = function writeInt8 (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 1, 0x7f, -0x80)
  if (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value)
  if (value < 0) value = 0xff + value + 1
  this[offset] = (value & 0xff)
  return offset + 1
}

Buffer.prototype.writeInt16LE = function writeInt16LE (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value & 0xff)
    this[offset + 1] = (value >>> 8)
  } else {
    objectWriteUInt16(this, value, offset, true)
  }
  return offset + 2
}

Buffer.prototype.writeInt16BE = function writeInt16BE (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 8)
    this[offset + 1] = (value & 0xff)
  } else {
    objectWriteUInt16(this, value, offset, false)
  }
  return offset + 2
}

Buffer.prototype.writeInt32LE = function writeInt32LE (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value & 0xff)
    this[offset + 1] = (value >>> 8)
    this[offset + 2] = (value >>> 16)
    this[offset + 3] = (value >>> 24)
  } else {
    objectWriteUInt32(this, value, offset, true)
  }
  return offset + 4
}

Buffer.prototype.writeInt32BE = function writeInt32BE (value, offset, noAssert) {
  value = +value
  offset = offset | 0
  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
  if (value < 0) value = 0xffffffff + value + 1
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 24)
    this[offset + 1] = (value >>> 16)
    this[offset + 2] = (value >>> 8)
    this[offset + 3] = (value & 0xff)
  } else {
    objectWriteUInt32(this, value, offset, false)
  }
  return offset + 4
}

function checkIEEE754 (buf, value, offset, ext, max, min) {
  if (offset + ext > buf.length) throw new RangeError('Index out of range')
  if (offset < 0) throw new RangeError('Index out of range')
}

function writeFloat (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    checkIEEE754(buf, value, offset, 4, 3.4028234663852886e+38, -3.4028234663852886e+38)
  }
  ieee754.write(buf, value, offset, littleEndian, 23, 4)
  return offset + 4
}

Buffer.prototype.writeFloatLE = function writeFloatLE (value, offset, noAssert) {
  return writeFloat(this, value, offset, true, noAssert)
}

Buffer.prototype.writeFloatBE = function writeFloatBE (value, offset, noAssert) {
  return writeFloat(this, value, offset, false, noAssert)
}

function writeDouble (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    checkIEEE754(buf, value, offset, 8, 1.7976931348623157E+308, -1.7976931348623157E+308)
  }
  ieee754.write(buf, value, offset, littleEndian, 52, 8)
  return offset + 8
}

Buffer.prototype.writeDoubleLE = function writeDoubleLE (value, offset, noAssert) {
  return writeDouble(this, value, offset, true, noAssert)
}

Buffer.prototype.writeDoubleBE = function writeDoubleBE (value, offset, noAssert) {
  return writeDouble(this, value, offset, false, noAssert)
}

// copy(targetBuffer, targetStart=0, sourceStart=0, sourceEnd=buffer.length)
Buffer.prototype.copy = function copy (target, targetStart, start, end) {
  if (!start) start = 0
  if (!end && end !== 0) end = this.length
  if (targetStart >= target.length) targetStart = target.length
  if (!targetStart) targetStart = 0
  if (end > 0 && end < start) end = start

  // Copy 0 bytes; we're done
  if (end === start) return 0
  if (target.length === 0 || this.length === 0) return 0

  // Fatal error conditions
  if (targetStart < 0) {
    throw new RangeError('targetStart out of bounds')
  }
  if (start < 0 || start >= this.length) throw new RangeError('sourceStart out of bounds')
  if (end < 0) throw new RangeError('sourceEnd out of bounds')

  // Are we oob?
  if (end > this.length) end = this.length
  if (target.length - targetStart < end - start) {
    end = target.length - targetStart + start
  }

  var len = end - start
  var i

  if (this === target && start < targetStart && targetStart < end) {
    // descending copy from end
    for (i = len - 1; i >= 0; --i) {
      target[i + targetStart] = this[i + start]
    }
  } else if (len < 1000 || !Buffer.TYPED_ARRAY_SUPPORT) {
    // ascending copy from start
    for (i = 0; i < len; ++i) {
      target[i + targetStart] = this[i + start]
    }
  } else {
    Uint8Array.prototype.set.call(
      target,
      this.subarray(start, start + len),
      targetStart
    )
  }

  return len
}

// Usage:
//    buffer.fill(number[, offset[, end]])
//    buffer.fill(buffer[, offset[, end]])
//    buffer.fill(string[, offset[, end]][, encoding])
Buffer.prototype.fill = function fill (val, start, end, encoding) {
  // Handle string cases:
  if (typeof val === 'string') {
    if (typeof start === 'string') {
      encoding = start
      start = 0
      end = this.length
    } else if (typeof end === 'string') {
      encoding = end
      end = this.length
    }
    if (val.length === 1) {
      var code = val.charCodeAt(0)
      if (code < 256) {
        val = code
      }
    }
    if (encoding !== undefined && typeof encoding !== 'string') {
      throw new TypeError('encoding must be a string')
    }
    if (typeof encoding === 'string' && !Buffer.isEncoding(encoding)) {
      throw new TypeError('Unknown encoding: ' + encoding)
    }
  } else if (typeof val === 'number') {
    val = val & 255
  }

  // Invalid ranges are not set to a default, so can range check early.
  if (start < 0 || this.length < start || this.length < end) {
    throw new RangeError('Out of range index')
  }

  if (end <= start) {
    return this
  }

  start = start >>> 0
  end = end === undefined ? this.length : end >>> 0

  if (!val) val = 0

  var i
  if (typeof val === 'number') {
    for (i = start; i < end; ++i) {
      this[i] = val
    }
  } else {
    var bytes = Buffer.isBuffer(val)
      ? val
      : utf8ToBytes(new Buffer(val, encoding).toString())
    var len = bytes.length
    for (i = 0; i < end - start; ++i) {
      this[i + start] = bytes[i % len]
    }
  }

  return this
}

// HELPER FUNCTIONS
// ================

var INVALID_BASE64_RE = /[^+\/0-9A-Za-z-_]/g

function base64clean (str) {
  // Node strips out invalid characters like \n and \t from the string, base64-js does not
  str = stringtrim(str).replace(INVALID_BASE64_RE, '')
  // Node converts strings with length < 2 to ''
  if (str.length < 2) return ''
  // Node allows for non-padded base64 strings (missing trailing ===), base64-js does not
  while (str.length % 4 !== 0) {
    str = str + '='
  }
  return str
}

function stringtrim (str) {
  if (str.trim) return str.trim()
  return str.replace(/^\s+|\s+$/g, '')
}

function toHex (n) {
  if (n < 16) return '0' + n.toString(16)
  return n.toString(16)
}

function utf8ToBytes (string, units) {
  units = units || Infinity
  var codePoint
  var length = string.length
  var leadSurrogate = null
  var bytes = []

  for (var i = 0; i < length; ++i) {
    codePoint = string.charCodeAt(i)

    // is surrogate component
    if (codePoint > 0xD7FF && codePoint < 0xE000) {
      // last char was a lead
      if (!leadSurrogate) {
        // no lead yet
        if (codePoint > 0xDBFF) {
          // unexpected trail
          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
          continue
        } else if (i + 1 === length) {
          // unpaired lead
          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
          continue
        }

        // valid lead
        leadSurrogate = codePoint

        continue
      }

      // 2 leads in a row
      if (codePoint < 0xDC00) {
        if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
        leadSurrogate = codePoint
        continue
      }

      // valid surrogate pair
      codePoint = (leadSurrogate - 0xD800 << 10 | codePoint - 0xDC00) + 0x10000
    } else if (leadSurrogate) {
      // valid bmp char, but last char was a lead
      if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
    }

    leadSurrogate = null

    // encode utf8
    if (codePoint < 0x80) {
      if ((units -= 1) < 0) break
      bytes.push(codePoint)
    } else if (codePoint < 0x800) {
      if ((units -= 2) < 0) break
      bytes.push(
        codePoint >> 0x6 | 0xC0,
        codePoint & 0x3F | 0x80
      )
    } else if (codePoint < 0x10000) {
      if ((units -= 3) < 0) break
      bytes.push(
        codePoint >> 0xC | 0xE0,
        codePoint >> 0x6 & 0x3F | 0x80,
        codePoint & 0x3F | 0x80
      )
    } else if (codePoint < 0x110000) {
      if ((units -= 4) < 0) break
      bytes.push(
        codePoint >> 0x12 | 0xF0,
        codePoint >> 0xC & 0x3F | 0x80,
        codePoint >> 0x6 & 0x3F | 0x80,
        codePoint & 0x3F | 0x80
      )
    } else {
      throw new Error('Invalid code point')
    }
  }

  return bytes
}

function asciiToBytes (str) {
  var byteArray = []
  for (var i = 0; i < str.length; ++i) {
    // Node's code seems to be doing this and not & 0x7F..
    byteArray.push(str.charCodeAt(i) & 0xFF)
  }
  return byteArray
}

function utf16leToBytes (str, units) {
  var c, hi, lo
  var byteArray = []
  for (var i = 0; i < str.length; ++i) {
    if ((units -= 2) < 0) break

    c = str.charCodeAt(i)
    hi = c >> 8
    lo = c % 256
    byteArray.push(lo)
    byteArray.push(hi)
  }

  return byteArray
}

function base64ToBytes (str) {
  return base64.toByteArray(base64clean(str))
}

function blitBuffer (src, dst, offset, length) {
  for (var i = 0; i < length; ++i) {
    if ((i + offset >= dst.length) || (i >= src.length)) break
    dst[i + offset] = src[i]
  }
  return i
}

function isnan (val) {
  return val !== val // eslint-disable-line no-self-compare
}

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"base64-js":102,"ieee754":108,"isarray":111}],106:[function(require,module,exports){
(function (Buffer){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.

function isArray(arg) {
  if (Array.isArray) {
    return Array.isArray(arg);
  }
  return objectToString(arg) === '[object Array]';
}
exports.isArray = isArray;

function isBoolean(arg) {
  return typeof arg === 'boolean';
}
exports.isBoolean = isBoolean;

function isNull(arg) {
  return arg === null;
}
exports.isNull = isNull;

function isNullOrUndefined(arg) {
  return arg == null;
}
exports.isNullOrUndefined = isNullOrUndefined;

function isNumber(arg) {
  return typeof arg === 'number';
}
exports.isNumber = isNumber;

function isString(arg) {
  return typeof arg === 'string';
}
exports.isString = isString;

function isSymbol(arg) {
  return typeof arg === 'symbol';
}
exports.isSymbol = isSymbol;

function isUndefined(arg) {
  return arg === void 0;
}
exports.isUndefined = isUndefined;

function isRegExp(re) {
  return objectToString(re) === '[object RegExp]';
}
exports.isRegExp = isRegExp;

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}
exports.isObject = isObject;

function isDate(d) {
  return objectToString(d) === '[object Date]';
}
exports.isDate = isDate;

function isError(e) {
  return (objectToString(e) === '[object Error]' || e instanceof Error);
}
exports.isError = isError;

function isFunction(arg) {
  return typeof arg === 'function';
}
exports.isFunction = isFunction;

function isPrimitive(arg) {
  return arg === null ||
         typeof arg === 'boolean' ||
         typeof arg === 'number' ||
         typeof arg === 'string' ||
         typeof arg === 'symbol' ||  // ES6 symbol
         typeof arg === 'undefined';
}
exports.isPrimitive = isPrimitive;

exports.isBuffer = Buffer.isBuffer;

function objectToString(o) {
  return Object.prototype.toString.call(o);
}

}).call(this,{"isBuffer":require("../../is-buffer/index.js")})
},{"../../is-buffer/index.js":110}],107:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

function EventEmitter() {
  this._events = this._events || {};
  this._maxListeners = this._maxListeners || undefined;
}
module.exports = EventEmitter;

// Backwards-compat with node 0.10.x
EventEmitter.EventEmitter = EventEmitter;

EventEmitter.prototype._events = undefined;
EventEmitter.prototype._maxListeners = undefined;

// By default EventEmitters will print a warning if more than 10 listeners are
// added to it. This is a useful default which helps finding memory leaks.
EventEmitter.defaultMaxListeners = 10;

// Obviously not all Emitters should be limited to 10. This function allows
// that to be increased. Set to zero for unlimited.
EventEmitter.prototype.setMaxListeners = function(n) {
  if (!isNumber(n) || n < 0 || isNaN(n))
    throw TypeError('n must be a positive number');
  this._maxListeners = n;
  return this;
};

EventEmitter.prototype.emit = function(type) {
  var er, handler, len, args, i, listeners;

  if (!this._events)
    this._events = {};

  // If there is no 'error' event listener then throw.
  if (type === 'error') {
    if (!this._events.error ||
        (isObject(this._events.error) && !this._events.error.length)) {
      er = arguments[1];
      if (er instanceof Error) {
        throw er; // Unhandled 'error' event
      } else {
        // At least give some kind of context to the user
        var err = new Error('Uncaught, unspecified "error" event. (' + er + ')');
        err.context = er;
        throw err;
      }
    }
  }

  handler = this._events[type];

  if (isUndefined(handler))
    return false;

  if (isFunction(handler)) {
    switch (arguments.length) {
      // fast cases
      case 1:
        handler.call(this);
        break;
      case 2:
        handler.call(this, arguments[1]);
        break;
      case 3:
        handler.call(this, arguments[1], arguments[2]);
        break;
      // slower
      default:
        args = Array.prototype.slice.call(arguments, 1);
        handler.apply(this, args);
    }
  } else if (isObject(handler)) {
    args = Array.prototype.slice.call(arguments, 1);
    listeners = handler.slice();
    len = listeners.length;
    for (i = 0; i < len; i++)
      listeners[i].apply(this, args);
  }

  return true;
};

EventEmitter.prototype.addListener = function(type, listener) {
  var m;

  if (!isFunction(listener))
    throw TypeError('listener must be a function');

  if (!this._events)
    this._events = {};

  // To avoid recursion in the case that type === "newListener"! Before
  // adding it to the listeners, first emit "newListener".
  if (this._events.newListener)
    this.emit('newListener', type,
              isFunction(listener.listener) ?
              listener.listener : listener);

  if (!this._events[type])
    // Optimize the case of one listener. Don't need the extra array object.
    this._events[type] = listener;
  else if (isObject(this._events[type]))
    // If we've already got an array, just append.
    this._events[type].push(listener);
  else
    // Adding the second element, need to change to array.
    this._events[type] = [this._events[type], listener];

  // Check for listener leak
  if (isObject(this._events[type]) && !this._events[type].warned) {
    if (!isUndefined(this._maxListeners)) {
      m = this._maxListeners;
    } else {
      m = EventEmitter.defaultMaxListeners;
    }

    if (m && m > 0 && this._events[type].length > m) {
      this._events[type].warned = true;
      console.error('(node) warning: possible EventEmitter memory ' +
                    'leak detected. %d listeners added. ' +
                    'Use emitter.setMaxListeners() to increase limit.',
                    this._events[type].length);
      if (typeof console.trace === 'function') {
        // not supported in IE 10
        console.trace();
      }
    }
  }

  return this;
};

EventEmitter.prototype.on = EventEmitter.prototype.addListener;

EventEmitter.prototype.once = function(type, listener) {
  if (!isFunction(listener))
    throw TypeError('listener must be a function');

  var fired = false;

  function g() {
    this.removeListener(type, g);

    if (!fired) {
      fired = true;
      listener.apply(this, arguments);
    }
  }

  g.listener = listener;
  this.on(type, g);

  return this;
};

// emits a 'removeListener' event iff the listener was removed
EventEmitter.prototype.removeListener = function(type, listener) {
  var list, position, length, i;

  if (!isFunction(listener))
    throw TypeError('listener must be a function');

  if (!this._events || !this._events[type])
    return this;

  list = this._events[type];
  length = list.length;
  position = -1;

  if (list === listener ||
      (isFunction(list.listener) && list.listener === listener)) {
    delete this._events[type];
    if (this._events.removeListener)
      this.emit('removeListener', type, listener);

  } else if (isObject(list)) {
    for (i = length; i-- > 0;) {
      if (list[i] === listener ||
          (list[i].listener && list[i].listener === listener)) {
        position = i;
        break;
      }
    }

    if (position < 0)
      return this;

    if (list.length === 1) {
      list.length = 0;
      delete this._events[type];
    } else {
      list.splice(position, 1);
    }

    if (this._events.removeListener)
      this.emit('removeListener', type, listener);
  }

  return this;
};

EventEmitter.prototype.removeAllListeners = function(type) {
  var key, listeners;

  if (!this._events)
    return this;

  // not listening for removeListener, no need to emit
  if (!this._events.removeListener) {
    if (arguments.length === 0)
      this._events = {};
    else if (this._events[type])
      delete this._events[type];
    return this;
  }

  // emit removeListener for all listeners on all events
  if (arguments.length === 0) {
    for (key in this._events) {
      if (key === 'removeListener') continue;
      this.removeAllListeners(key);
    }
    this.removeAllListeners('removeListener');
    this._events = {};
    return this;
  }

  listeners = this._events[type];

  if (isFunction(listeners)) {
    this.removeListener(type, listeners);
  } else if (listeners) {
    // LIFO order
    while (listeners.length)
      this.removeListener(type, listeners[listeners.length - 1]);
  }
  delete this._events[type];

  return this;
};

EventEmitter.prototype.listeners = function(type) {
  var ret;
  if (!this._events || !this._events[type])
    ret = [];
  else if (isFunction(this._events[type]))
    ret = [this._events[type]];
  else
    ret = this._events[type].slice();
  return ret;
};

EventEmitter.prototype.listenerCount = function(type) {
  if (this._events) {
    var evlistener = this._events[type];

    if (isFunction(evlistener))
      return 1;
    else if (evlistener)
      return evlistener.length;
  }
  return 0;
};

EventEmitter.listenerCount = function(emitter, type) {
  return emitter.listenerCount(type);
};

function isFunction(arg) {
  return typeof arg === 'function';
}

function isNumber(arg) {
  return typeof arg === 'number';
}

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}

function isUndefined(arg) {
  return arg === void 0;
}

},{}],108:[function(require,module,exports){
exports.read = function (buffer, offset, isLE, mLen, nBytes) {
  var e, m
  var eLen = nBytes * 8 - mLen - 1
  var eMax = (1 << eLen) - 1
  var eBias = eMax >> 1
  var nBits = -7
  var i = isLE ? (nBytes - 1) : 0
  var d = isLE ? -1 : 1
  var s = buffer[offset + i]

  i += d

  e = s & ((1 << (-nBits)) - 1)
  s >>= (-nBits)
  nBits += eLen
  for (; nBits > 0; e = e * 256 + buffer[offset + i], i += d, nBits -= 8) {}

  m = e & ((1 << (-nBits)) - 1)
  e >>= (-nBits)
  nBits += mLen
  for (; nBits > 0; m = m * 256 + buffer[offset + i], i += d, nBits -= 8) {}

  if (e === 0) {
    e = 1 - eBias
  } else if (e === eMax) {
    return m ? NaN : ((s ? -1 : 1) * Infinity)
  } else {
    m = m + Math.pow(2, mLen)
    e = e - eBias
  }
  return (s ? -1 : 1) * m * Math.pow(2, e - mLen)
}

exports.write = function (buffer, value, offset, isLE, mLen, nBytes) {
  var e, m, c
  var eLen = nBytes * 8 - mLen - 1
  var eMax = (1 << eLen) - 1
  var eBias = eMax >> 1
  var rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0)
  var i = isLE ? 0 : (nBytes - 1)
  var d = isLE ? 1 : -1
  var s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0

  value = Math.abs(value)

  if (isNaN(value) || value === Infinity) {
    m = isNaN(value) ? 1 : 0
    e = eMax
  } else {
    e = Math.floor(Math.log(value) / Math.LN2)
    if (value * (c = Math.pow(2, -e)) < 1) {
      e--
      c *= 2
    }
    if (e + eBias >= 1) {
      value += rt / c
    } else {
      value += rt * Math.pow(2, 1 - eBias)
    }
    if (value * c >= 2) {
      e++
      c /= 2
    }

    if (e + eBias >= eMax) {
      m = 0
      e = eMax
    } else if (e + eBias >= 1) {
      m = (value * c - 1) * Math.pow(2, mLen)
      e = e + eBias
    } else {
      m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen)
      e = 0
    }
  }

  for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8) {}

  e = (e << mLen) | m
  eLen += mLen
  for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8) {}

  buffer[offset + i - d] |= s * 128
}

},{}],109:[function(require,module,exports){
arguments[4][28][0].apply(exports,arguments)
},{"dup":28}],110:[function(require,module,exports){
/*!
 * Determine if an object is a Buffer
 *
 * @author   Feross Aboukhadijeh <feross@feross.org> <http://feross.org>
 * @license  MIT
 */

// The _isBuffer check is for Safari 5-7 support, because it's missing
// Object.prototype.constructor. Remove this eventually
module.exports = function (obj) {
  return obj != null && (isBuffer(obj) || isSlowBuffer(obj) || !!obj._isBuffer)
}

function isBuffer (obj) {
  return !!obj.constructor && typeof obj.constructor.isBuffer === 'function' && obj.constructor.isBuffer(obj)
}

// For Node v0.10 support. Remove this eventually.
function isSlowBuffer (obj) {
  return typeof obj.readFloatLE === 'function' && typeof obj.slice === 'function' && isBuffer(obj.slice(0, 0))
}

},{}],111:[function(require,module,exports){
arguments[4][90][0].apply(exports,arguments)
},{"dup":90}],112:[function(require,module,exports){
arguments[4][70][0].apply(exports,arguments)
},{"_process":113,"dup":70}],113:[function(require,module,exports){
// shim for using process in browser
var process = module.exports = {};

// cached from whatever global is present so that test runners that stub it
// don't break things.  But we need to wrap it in a try catch in case it is
// wrapped in strict mode code which doesn't define any globals.  It's inside a
// function because try/catches deoptimize in certain engines.

var cachedSetTimeout;
var cachedClearTimeout;

function defaultSetTimout() {
    throw new Error('setTimeout has not been defined');
}
function defaultClearTimeout () {
    throw new Error('clearTimeout has not been defined');
}
(function () {
    try {
        if (typeof setTimeout === 'function') {
            cachedSetTimeout = setTimeout;
        } else {
            cachedSetTimeout = defaultSetTimout;
        }
    } catch (e) {
        cachedSetTimeout = defaultSetTimout;
    }
    try {
        if (typeof clearTimeout === 'function') {
            cachedClearTimeout = clearTimeout;
        } else {
            cachedClearTimeout = defaultClearTimeout;
        }
    } catch (e) {
        cachedClearTimeout = defaultClearTimeout;
    }
} ())
function runTimeout(fun) {
    if (cachedSetTimeout === setTimeout) {
        //normal enviroments in sane situations
        return setTimeout(fun, 0);
    }
    // if setTimeout wasn't available but was latter defined
    if ((cachedSetTimeout === defaultSetTimout || !cachedSetTimeout) && setTimeout) {
        cachedSetTimeout = setTimeout;
        return setTimeout(fun, 0);
    }
    try {
        // when when somebody has screwed with setTimeout but no I.E. maddness
        return cachedSetTimeout(fun, 0);
    } catch(e){
        try {
            // When we are in I.E. but the script has been evaled so I.E. doesn't trust the global object when called normally
            return cachedSetTimeout.call(null, fun, 0);
        } catch(e){
            // same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error
            return cachedSetTimeout.call(this, fun, 0);
        }
    }


}
function runClearTimeout(marker) {
    if (cachedClearTimeout === clearTimeout) {
        //normal enviroments in sane situations
        return clearTimeout(marker);
    }
    // if clearTimeout wasn't available but was latter defined
    if ((cachedClearTimeout === defaultClearTimeout || !cachedClearTimeout) && clearTimeout) {
        cachedClearTimeout = clearTimeout;
        return clearTimeout(marker);
    }
    try {
        // when when somebody has screwed with setTimeout but no I.E. maddness
        return cachedClearTimeout(marker);
    } catch (e){
        try {
            // When we are in I.E. but the script has been evaled so I.E. doesn't  trust the global object when called normally
            return cachedClearTimeout.call(null, marker);
        } catch (e){
            // same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error.
            // Some versions of I.E. have different rules for clearTimeout vs setTimeout
            return cachedClearTimeout.call(this, marker);
        }
    }



}
var queue = [];
var draining = false;
var currentQueue;
var queueIndex = -1;

function cleanUpNextTick() {
    if (!draining || !currentQueue) {
        return;
    }
    draining = false;
    if (currentQueue.length) {
        queue = currentQueue.concat(queue);
    } else {
        queueIndex = -1;
    }
    if (queue.length) {
        drainQueue();
    }
}

function drainQueue() {
    if (draining) {
        return;
    }
    var timeout = runTimeout(cleanUpNextTick);
    draining = true;

    var len = queue.length;
    while(len) {
        currentQueue = queue;
        queue = [];
        while (++queueIndex < len) {
            if (currentQueue) {
                currentQueue[queueIndex].run();
            }
        }
        queueIndex = -1;
        len = queue.length;
    }
    currentQueue = null;
    draining = false;
    runClearTimeout(timeout);
}

process.nextTick = function (fun) {
    var args = new Array(arguments.length - 1);
    if (arguments.length > 1) {
        for (var i = 1; i < arguments.length; i++) {
            args[i - 1] = arguments[i];
        }
    }
    queue.push(new Item(fun, args));
    if (queue.length === 1 && !draining) {
        runTimeout(drainQueue);
    }
};

// v8 likes predictible objects
function Item(fun, array) {
    this.fun = fun;
    this.array = array;
}
Item.prototype.run = function () {
    this.fun.apply(null, this.array);
};
process.title = 'browser';
process.browser = true;
process.env = {};
process.argv = [];
process.version = ''; // empty string to avoid regexp issues
process.versions = {};

function noop() {}

process.on = noop;
process.addListener = noop;
process.once = noop;
process.off = noop;
process.removeListener = noop;
process.removeAllListeners = noop;
process.emit = noop;

process.binding = function (name) {
    throw new Error('process.binding is not supported');
};

process.cwd = function () { return '/' };
process.chdir = function (dir) {
    throw new Error('process.chdir is not supported');
};
process.umask = function() { return 0; };

},{}],114:[function(require,module,exports){
module.exports = require("./lib/_stream_duplex.js")

},{"./lib/_stream_duplex.js":115}],115:[function(require,module,exports){
arguments[4][91][0].apply(exports,arguments)
},{"./_stream_readable":117,"./_stream_writable":119,"core-util-is":106,"dup":91,"inherits":109,"process-nextick-args":112}],116:[function(require,module,exports){
// a passthrough stream.
// basically just the most minimal sort of Transform stream.
// Every written chunk gets output as-is.

'use strict';

module.exports = PassThrough;

var Transform = require('./_stream_transform');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

util.inherits(PassThrough, Transform);

function PassThrough(options) {
  if (!(this instanceof PassThrough)) return new PassThrough(options);

  Transform.call(this, options);
}

PassThrough.prototype._transform = function (chunk, encoding, cb) {
  cb(null, chunk);
};
},{"./_stream_transform":118,"core-util-is":106,"inherits":109}],117:[function(require,module,exports){
(function (process){
'use strict';

module.exports = Readable;

/*<replacement>*/
var processNextTick = require('process-nextick-args');
/*</replacement>*/

/*<replacement>*/
var isArray = require('isarray');
/*</replacement>*/

Readable.ReadableState = ReadableState;

/*<replacement>*/
var EE = require('events').EventEmitter;

var EElistenerCount = function (emitter, type) {
  return emitter.listeners(type).length;
};
/*</replacement>*/

/*<replacement>*/
var Stream;
(function () {
  try {
    Stream = require('st' + 'ream');
  } catch (_) {} finally {
    if (!Stream) Stream = require('events').EventEmitter;
  }
})();
/*</replacement>*/

var Buffer = require('buffer').Buffer;
/*<replacement>*/
var bufferShim = require('buffer-shims');
/*</replacement>*/

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

/*<replacement>*/
var debugUtil = require('util');
var debug = void 0;
if (debugUtil && debugUtil.debuglog) {
  debug = debugUtil.debuglog('stream');
} else {
  debug = function () {};
}
/*</replacement>*/

var BufferList = require('./internal/streams/BufferList');
var StringDecoder;

util.inherits(Readable, Stream);

function prependListener(emitter, event, fn) {
  if (typeof emitter.prependListener === 'function') {
    return emitter.prependListener(event, fn);
  } else {
    // This is a hack to make sure that our error handler is attached before any
    // userland ones.  NEVER DO THIS. This is here only because this code needs
    // to continue to work with older versions of Node.js that do not include
    // the prependListener() method. The goal is to eventually remove this hack.
    if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
  }
}

var Duplex;
function ReadableState(options, stream) {
  Duplex = Duplex || require('./_stream_duplex');

  options = options || {};

  // object stream flag. Used to make read(n) ignore n and to
  // make all the buffer merging and length checks go away
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex) this.objectMode = this.objectMode || !!options.readableObjectMode;

  // the point at which it stops calling _read() to fill the buffer
  // Note: 0 is a valid value, means "don't call _read preemptively ever"
  var hwm = options.highWaterMark;
  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = hwm || hwm === 0 ? hwm : defaultHwm;

  // cast to ints.
  this.highWaterMark = ~ ~this.highWaterMark;

  // A linked list is used to store data chunks instead of an array because the
  // linked list can remove elements from the beginning faster than
  // array.shift()
  this.buffer = new BufferList();
  this.length = 0;
  this.pipes = null;
  this.pipesCount = 0;
  this.flowing = null;
  this.ended = false;
  this.endEmitted = false;
  this.reading = false;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // whenever we return null, then we set a flag to say
  // that we're awaiting a 'readable' event emission.
  this.needReadable = false;
  this.emittedReadable = false;
  this.readableListening = false;
  this.resumeScheduled = false;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // when piping, we only care about 'readable' events that happen
  // after read()ing all the bytes and not getting any pushback.
  this.ranOut = false;

  // the number of writers that are awaiting a drain event in .pipe()s
  this.awaitDrain = 0;

  // if true, a maybeReadMore has been scheduled
  this.readingMore = false;

  this.decoder = null;
  this.encoding = null;
  if (options.encoding) {
    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
    this.decoder = new StringDecoder(options.encoding);
    this.encoding = options.encoding;
  }
}

var Duplex;
function Readable(options) {
  Duplex = Duplex || require('./_stream_duplex');

  if (!(this instanceof Readable)) return new Readable(options);

  this._readableState = new ReadableState(options, this);

  // legacy
  this.readable = true;

  if (options && typeof options.read === 'function') this._read = options.read;

  Stream.call(this);
}

// Manually shove something into the read() buffer.
// This returns true if the highWaterMark has not been hit yet,
// similar to how Writable.write() returns true if you should
// write() some more.
Readable.prototype.push = function (chunk, encoding) {
  var state = this._readableState;

  if (!state.objectMode && typeof chunk === 'string') {
    encoding = encoding || state.defaultEncoding;
    if (encoding !== state.encoding) {
      chunk = bufferShim.from(chunk, encoding);
      encoding = '';
    }
  }

  return readableAddChunk(this, state, chunk, encoding, false);
};

// Unshift should *always* be something directly out of read()
Readable.prototype.unshift = function (chunk) {
  var state = this._readableState;
  return readableAddChunk(this, state, chunk, '', true);
};

Readable.prototype.isPaused = function () {
  return this._readableState.flowing === false;
};

function readableAddChunk(stream, state, chunk, encoding, addToFront) {
  var er = chunkInvalid(state, chunk);
  if (er) {
    stream.emit('error', er);
  } else if (chunk === null) {
    state.reading = false;
    onEofChunk(stream, state);
  } else if (state.objectMode || chunk && chunk.length > 0) {
    if (state.ended && !addToFront) {
      var e = new Error('stream.push() after EOF');
      stream.emit('error', e);
    } else if (state.endEmitted && addToFront) {
      var _e = new Error('stream.unshift() after end event');
      stream.emit('error', _e);
    } else {
      var skipAdd;
      if (state.decoder && !addToFront && !encoding) {
        chunk = state.decoder.write(chunk);
        skipAdd = !state.objectMode && chunk.length === 0;
      }

      if (!addToFront) state.reading = false;

      // Don't add to the buffer if we've decoded to an empty string chunk and
      // we're not in object mode
      if (!skipAdd) {
        // if we want the data now, just emit it.
        if (state.flowing && state.length === 0 && !state.sync) {
          stream.emit('data', chunk);
          stream.read(0);
        } else {
          // update the buffer info.
          state.length += state.objectMode ? 1 : chunk.length;
          if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);

          if (state.needReadable) emitReadable(stream);
        }
      }

      maybeReadMore(stream, state);
    }
  } else if (!addToFront) {
    state.reading = false;
  }

  return needMoreData(state);
}

// if it's past the high water mark, we can push in some more.
// Also, if we have no data yet, we can stand some
// more bytes.  This is to work around cases where hwm=0,
// such as the repl.  Also, if the push() triggered a
// readable event, and the user called read(largeNumber) such that
// needReadable was set, then we ought to push more, so that another
// 'readable' event will be triggered.
function needMoreData(state) {
  return !state.ended && (state.needReadable || state.length < state.highWaterMark || state.length === 0);
}

// backwards compatibility.
Readable.prototype.setEncoding = function (enc) {
  if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
  this._readableState.decoder = new StringDecoder(enc);
  this._readableState.encoding = enc;
  return this;
};

// Don't raise the hwm > 8MB
var MAX_HWM = 0x800000;
function computeNewHighWaterMark(n) {
  if (n >= MAX_HWM) {
    n = MAX_HWM;
  } else {
    // Get the next highest power of 2 to prevent increasing hwm excessively in
    // tiny amounts
    n--;
    n |= n >>> 1;
    n |= n >>> 2;
    n |= n >>> 4;
    n |= n >>> 8;
    n |= n >>> 16;
    n++;
  }
  return n;
}

// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function howMuchToRead(n, state) {
  if (n <= 0 || state.length === 0 && state.ended) return 0;
  if (state.objectMode) return 1;
  if (n !== n) {
    // Only flow one buffer at a time
    if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
  }
  // If we're asking for more than the current hwm, then raise the hwm.
  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
  if (n <= state.length) return n;
  // Don't have enough
  if (!state.ended) {
    state.needReadable = true;
    return 0;
  }
  return state.length;
}

// you can override either this method, or the async _read(n) below.
Readable.prototype.read = function (n) {
  debug('read', n);
  n = parseInt(n, 10);
  var state = this._readableState;
  var nOrig = n;

  if (n !== 0) state.emittedReadable = false;

  // if we're doing read(0) to trigger a readable event, but we
  // already have a bunch of data in the buffer, then just trigger
  // the 'readable' event and move on.
  if (n === 0 && state.needReadable && (state.length >= state.highWaterMark || state.ended)) {
    debug('read: emitReadable', state.length, state.ended);
    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
    return null;
  }

  n = howMuchToRead(n, state);

  // if we've ended, and we're now clear, then finish it up.
  if (n === 0 && state.ended) {
    if (state.length === 0) endReadable(this);
    return null;
  }

  // All the actual chunk generation logic needs to be
  // *below* the call to _read.  The reason is that in certain
  // synthetic stream cases, such as passthrough streams, _read
  // may be a completely synchronous operation which may change
  // the state of the read buffer, providing enough data when
  // before there was *not* enough.
  //
  // So, the steps are:
  // 1. Figure out what the state of things will be after we do
  // a read from the buffer.
  //
  // 2. If that resulting state will trigger a _read, then call _read.
  // Note that this may be asynchronous, or synchronous.  Yes, it is
  // deeply ugly to write APIs this way, but that still doesn't mean
  // that the Readable class should behave improperly, as streams are
  // designed to be sync/async agnostic.
  // Take note if the _read call is sync or async (ie, if the read call
  // has returned yet), so that we know whether or not it's safe to emit
  // 'readable' etc.
  //
  // 3. Actually pull the requested chunks out of the buffer and return.

  // if we need a readable event, then we need to do some reading.
  var doRead = state.needReadable;
  debug('need readable', doRead);

  // if we currently have less than the highWaterMark, then also read some
  if (state.length === 0 || state.length - n < state.highWaterMark) {
    doRead = true;
    debug('length less than watermark', doRead);
  }

  // however, if we've ended, then there's no point, and if we're already
  // reading, then it's unnecessary.
  if (state.ended || state.reading) {
    doRead = false;
    debug('reading or ended', doRead);
  } else if (doRead) {
    debug('do read');
    state.reading = true;
    state.sync = true;
    // if the length is currently zero, then we *need* a readable event.
    if (state.length === 0) state.needReadable = true;
    // call internal read method
    this._read(state.highWaterMark);
    state.sync = false;
    // If _read pushed data synchronously, then `reading` will be false,
    // and we need to re-evaluate how much data we can return to the user.
    if (!state.reading) n = howMuchToRead(nOrig, state);
  }

  var ret;
  if (n > 0) ret = fromList(n, state);else ret = null;

  if (ret === null) {
    state.needReadable = true;
    n = 0;
  } else {
    state.length -= n;
  }

  if (state.length === 0) {
    // If we have nothing in the buffer, then we want to know
    // as soon as we *do* get something into the buffer.
    if (!state.ended) state.needReadable = true;

    // If we tried to read() past the EOF, then emit end on the next tick.
    if (nOrig !== n && state.ended) endReadable(this);
  }

  if (ret !== null) this.emit('data', ret);

  return ret;
};

function chunkInvalid(state, chunk) {
  var er = null;
  if (!Buffer.isBuffer(chunk) && typeof chunk !== 'string' && chunk !== null && chunk !== undefined && !state.objectMode) {
    er = new TypeError('Invalid non-string/buffer chunk');
  }
  return er;
}

function onEofChunk(stream, state) {
  if (state.ended) return;
  if (state.decoder) {
    var chunk = state.decoder.end();
    if (chunk && chunk.length) {
      state.buffer.push(chunk);
      state.length += state.objectMode ? 1 : chunk.length;
    }
  }
  state.ended = true;

  // emit 'readable' now to make sure it gets picked up.
  emitReadable(stream);
}

// Don't emit readable right away in sync mode, because this can trigger
// another read() call => stack overflow.  This way, it might trigger
// a nextTick recursion warning, but that's not so bad.
function emitReadable(stream) {
  var state = stream._readableState;
  state.needReadable = false;
  if (!state.emittedReadable) {
    debug('emitReadable', state.flowing);
    state.emittedReadable = true;
    if (state.sync) processNextTick(emitReadable_, stream);else emitReadable_(stream);
  }
}

function emitReadable_(stream) {
  debug('emit readable');
  stream.emit('readable');
  flow(stream);
}

// at this point, the user has presumably seen the 'readable' event,
// and called read() to consume some data.  that may have triggered
// in turn another _read(n) call, in which case reading = true if
// it's in progress.
// However, if we're not ended, or reading, and the length < hwm,
// then go ahead and try to read some more preemptively.
function maybeReadMore(stream, state) {
  if (!state.readingMore) {
    state.readingMore = true;
    processNextTick(maybeReadMore_, stream, state);
  }
}

function maybeReadMore_(stream, state) {
  var len = state.length;
  while (!state.reading && !state.flowing && !state.ended && state.length < state.highWaterMark) {
    debug('maybeReadMore read 0');
    stream.read(0);
    if (len === state.length)
      // didn't get any data, stop spinning.
      break;else len = state.length;
  }
  state.readingMore = false;
}

// abstract method.  to be overridden in specific implementation classes.
// call cb(er, data) where data is <= n in length.
// for virtual (non-string, non-buffer) streams, "length" is somewhat
// arbitrary, and perhaps not very meaningful.
Readable.prototype._read = function (n) {
  this.emit('error', new Error('not implemented'));
};

Readable.prototype.pipe = function (dest, pipeOpts) {
  var src = this;
  var state = this._readableState;

  switch (state.pipesCount) {
    case 0:
      state.pipes = dest;
      break;
    case 1:
      state.pipes = [state.pipes, dest];
      break;
    default:
      state.pipes.push(dest);
      break;
  }
  state.pipesCount += 1;
  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);

  var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;

  var endFn = doEnd ? onend : cleanup;
  if (state.endEmitted) processNextTick(endFn);else src.once('end', endFn);

  dest.on('unpipe', onunpipe);
  function onunpipe(readable) {
    debug('onunpipe');
    if (readable === src) {
      cleanup();
    }
  }

  function onend() {
    debug('onend');
    dest.end();
  }

  // when the dest drains, it reduces the awaitDrain counter
  // on the source.  This would be more elegant with a .once()
  // handler in flow(), but adding and removing repeatedly is
  // too slow.
  var ondrain = pipeOnDrain(src);
  dest.on('drain', ondrain);

  var cleanedUp = false;
  function cleanup() {
    debug('cleanup');
    // cleanup event handlers once the pipe is broken
    dest.removeListener('close', onclose);
    dest.removeListener('finish', onfinish);
    dest.removeListener('drain', ondrain);
    dest.removeListener('error', onerror);
    dest.removeListener('unpipe', onunpipe);
    src.removeListener('end', onend);
    src.removeListener('end', cleanup);
    src.removeListener('data', ondata);

    cleanedUp = true;

    // if the reader is waiting for a drain event from this
    // specific writer, then it would cause it to never start
    // flowing again.
    // So, if this is awaiting a drain, then we just call it now.
    // If we don't know, then assume that we are waiting for one.
    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
  }

  // If the user pushes more data while we're writing to dest then we'll end up
  // in ondata again. However, we only want to increase awaitDrain once because
  // dest will only emit one 'drain' event for the multiple writes.
  // => Introduce a guard on increasing awaitDrain.
  var increasedAwaitDrain = false;
  src.on('data', ondata);
  function ondata(chunk) {
    debug('ondata');
    increasedAwaitDrain = false;
    var ret = dest.write(chunk);
    if (false === ret && !increasedAwaitDrain) {
      // If the user unpiped during `dest.write()`, it is possible
      // to get stuck in a permanently paused state if that write
      // also returned false.
      // => Check whether `dest` is still a piping destination.
      if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
        debug('false write response, pause', src._readableState.awaitDrain);
        src._readableState.awaitDrain++;
        increasedAwaitDrain = true;
      }
      src.pause();
    }
  }

  // if the dest has an error, then stop piping into it.
  // however, don't suppress the throwing behavior for this.
  function onerror(er) {
    debug('onerror', er);
    unpipe();
    dest.removeListener('error', onerror);
    if (EElistenerCount(dest, 'error') === 0) dest.emit('error', er);
  }

  // Make sure our error handler is attached before userland ones.
  prependListener(dest, 'error', onerror);

  // Both close and finish should trigger unpipe, but only once.
  function onclose() {
    dest.removeListener('finish', onfinish);
    unpipe();
  }
  dest.once('close', onclose);
  function onfinish() {
    debug('onfinish');
    dest.removeListener('close', onclose);
    unpipe();
  }
  dest.once('finish', onfinish);

  function unpipe() {
    debug('unpipe');
    src.unpipe(dest);
  }

  // tell the dest that it's being piped to
  dest.emit('pipe', src);

  // start the flow if it hasn't been started already.
  if (!state.flowing) {
    debug('pipe resume');
    src.resume();
  }

  return dest;
};

function pipeOnDrain(src) {
  return function () {
    var state = src._readableState;
    debug('pipeOnDrain', state.awaitDrain);
    if (state.awaitDrain) state.awaitDrain--;
    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
      state.flowing = true;
      flow(src);
    }
  };
}

Readable.prototype.unpipe = function (dest) {
  var state = this._readableState;

  // if we're not piping anywhere, then do nothing.
  if (state.pipesCount === 0) return this;

  // just one destination.  most common case.
  if (state.pipesCount === 1) {
    // passed in one, but it's not the right one.
    if (dest && dest !== state.pipes) return this;

    if (!dest) dest = state.pipes;

    // got a match.
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;
    if (dest) dest.emit('unpipe', this);
    return this;
  }

  // slow case. multiple pipe destinations.

  if (!dest) {
    // remove all.
    var dests = state.pipes;
    var len = state.pipesCount;
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;

    for (var _i = 0; _i < len; _i++) {
      dests[_i].emit('unpipe', this);
    }return this;
  }

  // try to find the right one.
  var i = indexOf(state.pipes, dest);
  if (i === -1) return this;

  state.pipes.splice(i, 1);
  state.pipesCount -= 1;
  if (state.pipesCount === 1) state.pipes = state.pipes[0];

  dest.emit('unpipe', this);

  return this;
};

// set up data events if they are asked for
// Ensure readable listeners eventually get something
Readable.prototype.on = function (ev, fn) {
  var res = Stream.prototype.on.call(this, ev, fn);

  if (ev === 'data') {
    // Start flowing on next tick if stream isn't explicitly paused
    if (this._readableState.flowing !== false) this.resume();
  } else if (ev === 'readable') {
    var state = this._readableState;
    if (!state.endEmitted && !state.readableListening) {
      state.readableListening = state.needReadable = true;
      state.emittedReadable = false;
      if (!state.reading) {
        processNextTick(nReadingNextTick, this);
      } else if (state.length) {
        emitReadable(this, state);
      }
    }
  }

  return res;
};
Readable.prototype.addListener = Readable.prototype.on;

function nReadingNextTick(self) {
  debug('readable nexttick read 0');
  self.read(0);
}

// pause() and resume() are remnants of the legacy readable stream API
// If the user uses them, then switch into old mode.
Readable.prototype.resume = function () {
  var state = this._readableState;
  if (!state.flowing) {
    debug('resume');
    state.flowing = true;
    resume(this, state);
  }
  return this;
};

function resume(stream, state) {
  if (!state.resumeScheduled) {
    state.resumeScheduled = true;
    processNextTick(resume_, stream, state);
  }
}

function resume_(stream, state) {
  if (!state.reading) {
    debug('resume read 0');
    stream.read(0);
  }

  state.resumeScheduled = false;
  state.awaitDrain = 0;
  stream.emit('resume');
  flow(stream);
  if (state.flowing && !state.reading) stream.read(0);
}

Readable.prototype.pause = function () {
  debug('call pause flowing=%j', this._readableState.flowing);
  if (false !== this._readableState.flowing) {
    debug('pause');
    this._readableState.flowing = false;
    this.emit('pause');
  }
  return this;
};

function flow(stream) {
  var state = stream._readableState;
  debug('flow', state.flowing);
  while (state.flowing && stream.read() !== null) {}
}

// wrap an old-style stream as the async data source.
// This is *not* part of the readable stream interface.
// It is an ugly unfortunate mess of history.
Readable.prototype.wrap = function (stream) {
  var state = this._readableState;
  var paused = false;

  var self = this;
  stream.on('end', function () {
    debug('wrapped end');
    if (state.decoder && !state.ended) {
      var chunk = state.decoder.end();
      if (chunk && chunk.length) self.push(chunk);
    }

    self.push(null);
  });

  stream.on('data', function (chunk) {
    debug('wrapped data');
    if (state.decoder) chunk = state.decoder.write(chunk);

    // don't skip over falsy values in objectMode
    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;

    var ret = self.push(chunk);
    if (!ret) {
      paused = true;
      stream.pause();
    }
  });

  // proxy all the other methods.
  // important when wrapping filters and duplexes.
  for (var i in stream) {
    if (this[i] === undefined && typeof stream[i] === 'function') {
      this[i] = function (method) {
        return function () {
          return stream[method].apply(stream, arguments);
        };
      }(i);
    }
  }

  // proxy certain important events.
  var events = ['error', 'close', 'destroy', 'pause', 'resume'];
  forEach(events, function (ev) {
    stream.on(ev, self.emit.bind(self, ev));
  });

  // when we try to consume some more bytes, simply unpause the
  // underlying stream.
  self._read = function (n) {
    debug('wrapped _read', n);
    if (paused) {
      paused = false;
      stream.resume();
    }
  };

  return self;
};

// exposed for testing purposes only.
Readable._fromList = fromList;

// Pluck off n bytes from an array of buffers.
// Length is the combined lengths of all the buffers in the list.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function fromList(n, state) {
  // nothing buffered
  if (state.length === 0) return null;

  var ret;
  if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
    // read it all, truncate the list
    if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.head.data;else ret = state.buffer.concat(state.length);
    state.buffer.clear();
  } else {
    // read part of list
    ret = fromListPartial(n, state.buffer, state.decoder);
  }

  return ret;
}

// Extracts only enough buffered data to satisfy the amount requested.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function fromListPartial(n, list, hasStrings) {
  var ret;
  if (n < list.head.data.length) {
    // slice is the same for buffers and strings
    ret = list.head.data.slice(0, n);
    list.head.data = list.head.data.slice(n);
  } else if (n === list.head.data.length) {
    // first chunk is a perfect match
    ret = list.shift();
  } else {
    // result spans more than one buffer
    ret = hasStrings ? copyFromBufferString(n, list) : copyFromBuffer(n, list);
  }
  return ret;
}

// Copies a specified amount of characters from the list of buffered data
// chunks.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function copyFromBufferString(n, list) {
  var p = list.head;
  var c = 1;
  var ret = p.data;
  n -= ret.length;
  while (p = p.next) {
    var str = p.data;
    var nb = n > str.length ? str.length : n;
    if (nb === str.length) ret += str;else ret += str.slice(0, n);
    n -= nb;
    if (n === 0) {
      if (nb === str.length) {
        ++c;
        if (p.next) list.head = p.next;else list.head = list.tail = null;
      } else {
        list.head = p;
        p.data = str.slice(nb);
      }
      break;
    }
    ++c;
  }
  list.length -= c;
  return ret;
}

// Copies a specified amount of bytes from the list of buffered data chunks.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function copyFromBuffer(n, list) {
  var ret = bufferShim.allocUnsafe(n);
  var p = list.head;
  var c = 1;
  p.data.copy(ret);
  n -= p.data.length;
  while (p = p.next) {
    var buf = p.data;
    var nb = n > buf.length ? buf.length : n;
    buf.copy(ret, ret.length - n, 0, nb);
    n -= nb;
    if (n === 0) {
      if (nb === buf.length) {
        ++c;
        if (p.next) list.head = p.next;else list.head = list.tail = null;
      } else {
        list.head = p;
        p.data = buf.slice(nb);
      }
      break;
    }
    ++c;
  }
  list.length -= c;
  return ret;
}

function endReadable(stream) {
  var state = stream._readableState;

  // If we get here before consuming all the bytes, then that is a
  // bug in node.  Should never happen.
  if (state.length > 0) throw new Error('"endReadable()" called on non-empty stream');

  if (!state.endEmitted) {
    state.ended = true;
    processNextTick(endReadableNT, state, stream);
  }
}

function endReadableNT(state, stream) {
  // Check that we didn't get one last unshift.
  if (!state.endEmitted && state.length === 0) {
    state.endEmitted = true;
    stream.readable = false;
    stream.emit('end');
  }
}

function forEach(xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}

function indexOf(xs, x) {
  for (var i = 0, l = xs.length; i < l; i++) {
    if (xs[i] === x) return i;
  }
  return -1;
}
}).call(this,require('_process'))
},{"./_stream_duplex":115,"./internal/streams/BufferList":120,"_process":113,"buffer":105,"buffer-shims":104,"core-util-is":106,"events":107,"inherits":109,"isarray":111,"process-nextick-args":112,"string_decoder/":126,"util":103}],118:[function(require,module,exports){
// a transform stream is a readable/writable stream where you do
// something with the data.  Sometimes it's called a "filter",
// but that's not a great name for it, since that implies a thing where
// some bits pass through, and others are simply ignored.  (That would
// be a valid example of a transform, of course.)
//
// While the output is causally related to the input, it's not a
// necessarily symmetric or synchronous transformation.  For example,
// a zlib stream might take multiple plain-text writes(), and then
// emit a single compressed chunk some time in the future.
//
// Here's how this works:
//
// The Transform stream has all the aspects of the readable and writable
// stream classes.  When you write(chunk), that calls _write(chunk,cb)
// internally, and returns false if there's a lot of pending writes
// buffered up.  When you call read(), that calls _read(n) until
// there's enough pending readable data buffered up.
//
// In a transform stream, the written data is placed in a buffer.  When
// _read(n) is called, it transforms the queued up data, calling the
// buffered _write cb's as it consumes chunks.  If consuming a single
// written chunk would result in multiple output chunks, then the first
// outputted bit calls the readcb, and subsequent chunks just go into
// the read buffer, and will cause it to emit 'readable' if necessary.
//
// This way, back-pressure is actually determined by the reading side,
// since _read has to be called to start processing a new chunk.  However,
// a pathological inflate type of transform can cause excessive buffering
// here.  For example, imagine a stream where every byte of input is
// interpreted as an integer from 0-255, and then results in that many
// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
// 1kb of data being output.  In this case, you could write a very small
// amount of input, and end up with a very large amount of output.  In
// such a pathological inflating mechanism, there'd be no way to tell
// the system to stop doing the transform.  A single 4MB write could
// cause the system to run out of memory.
//
// However, even in such a pathological case, only a single written chunk
// would be consumed, and then the rest would wait (un-transformed) until
// the results of the previous transformed chunk were consumed.

'use strict';

module.exports = Transform;

var Duplex = require('./_stream_duplex');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

util.inherits(Transform, Duplex);

function TransformState(stream) {
  this.afterTransform = function (er, data) {
    return afterTransform(stream, er, data);
  };

  this.needTransform = false;
  this.transforming = false;
  this.writecb = null;
  this.writechunk = null;
  this.writeencoding = null;
}

function afterTransform(stream, er, data) {
  var ts = stream._transformState;
  ts.transforming = false;

  var cb = ts.writecb;

  if (!cb) return stream.emit('error', new Error('no writecb in Transform class'));

  ts.writechunk = null;
  ts.writecb = null;

  if (data !== null && data !== undefined) stream.push(data);

  cb(er);

  var rs = stream._readableState;
  rs.reading = false;
  if (rs.needReadable || rs.length < rs.highWaterMark) {
    stream._read(rs.highWaterMark);
  }
}

function Transform(options) {
  if (!(this instanceof Transform)) return new Transform(options);

  Duplex.call(this, options);

  this._transformState = new TransformState(this);

  // when the writable side finishes, then flush out anything remaining.
  var stream = this;

  // start out asking for a readable event once data is transformed.
  this._readableState.needReadable = true;

  // we have implemented the _read method, and done the other things
  // that Readable wants before the first _read call, so unset the
  // sync guard flag.
  this._readableState.sync = false;

  if (options) {
    if (typeof options.transform === 'function') this._transform = options.transform;

    if (typeof options.flush === 'function') this._flush = options.flush;
  }

  this.once('prefinish', function () {
    if (typeof this._flush === 'function') this._flush(function (er) {
      done(stream, er);
    });else done(stream);
  });
}

Transform.prototype.push = function (chunk, encoding) {
  this._transformState.needTransform = false;
  return Duplex.prototype.push.call(this, chunk, encoding);
};

// This is the part where you do stuff!
// override this function in implementation classes.
// 'chunk' is an input chunk.
//
// Call `push(newChunk)` to pass along transformed output
// to the readable side.  You may call 'push' zero or more times.
//
// Call `cb(err)` when you are done with this chunk.  If you pass
// an error, then that'll put the hurt on the whole operation.  If you
// never call cb(), then you'll never get another chunk.
Transform.prototype._transform = function (chunk, encoding, cb) {
  throw new Error('Not implemented');
};

Transform.prototype._write = function (chunk, encoding, cb) {
  var ts = this._transformState;
  ts.writecb = cb;
  ts.writechunk = chunk;
  ts.writeencoding = encoding;
  if (!ts.transforming) {
    var rs = this._readableState;
    if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
  }
};

// Doesn't matter what the args are here.
// _transform does all the work.
// That we got here means that the readable side wants more data.
Transform.prototype._read = function (n) {
  var ts = this._transformState;

  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
    ts.transforming = true;
    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
  } else {
    // mark that we need a transform, so that any data that comes in
    // will get processed, now that we've asked for it.
    ts.needTransform = true;
  }
};

function done(stream, er) {
  if (er) return stream.emit('error', er);

  // if there's nothing in the write buffer, then that means
  // that nothing more will ever be provided
  var ws = stream._writableState;
  var ts = stream._transformState;

  if (ws.length) throw new Error('Calling transform done when ws.length != 0');

  if (ts.transforming) throw new Error('Calling transform done when still transforming');

  return stream.push(null);
}
},{"./_stream_duplex":115,"core-util-is":106,"inherits":109}],119:[function(require,module,exports){
(function (process){
// A bit simpler than readable streams.
// Implement an async ._write(chunk, encoding, cb), and it'll handle all
// the drain event emission and buffering.

'use strict';

module.exports = Writable;

/*<replacement>*/
var processNextTick = require('process-nextick-args');
/*</replacement>*/

/*<replacement>*/
var asyncWrite = !process.browser && ['v0.10', 'v0.9.'].indexOf(process.version.slice(0, 5)) > -1 ? setImmediate : processNextTick;
/*</replacement>*/

Writable.WritableState = WritableState;

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

/*<replacement>*/
var internalUtil = {
  deprecate: require('util-deprecate')
};
/*</replacement>*/

/*<replacement>*/
var Stream;
(function () {
  try {
    Stream = require('st' + 'ream');
  } catch (_) {} finally {
    if (!Stream) Stream = require('events').EventEmitter;
  }
})();
/*</replacement>*/

var Buffer = require('buffer').Buffer;
/*<replacement>*/
var bufferShim = require('buffer-shims');
/*</replacement>*/

util.inherits(Writable, Stream);

function nop() {}

function WriteReq(chunk, encoding, cb) {
  this.chunk = chunk;
  this.encoding = encoding;
  this.callback = cb;
  this.next = null;
}

var Duplex;
function WritableState(options, stream) {
  Duplex = Duplex || require('./_stream_duplex');

  options = options || {};

  // object stream flag to indicate whether or not this stream
  // contains buffers or objects.
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex) this.objectMode = this.objectMode || !!options.writableObjectMode;

  // the point at which write() starts returning false
  // Note: 0 is a valid value, means that we always return false if
  // the entire buffer is not flushed immediately on write()
  var hwm = options.highWaterMark;
  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = hwm || hwm === 0 ? hwm : defaultHwm;

  // cast to ints.
  this.highWaterMark = ~ ~this.highWaterMark;

  this.needDrain = false;
  // at the start of calling end()
  this.ending = false;
  // when end() has been called, and returned
  this.ended = false;
  // when 'finish' is emitted
  this.finished = false;

  // should we decode strings into buffers before passing to _write?
  // this is here so that some node-core streams can optimize string
  // handling at a lower level.
  var noDecode = options.decodeStrings === false;
  this.decodeStrings = !noDecode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // not an actual buffer we keep track of, but a measurement
  // of how much we're waiting to get pushed to some underlying
  // socket or file.
  this.length = 0;

  // a flag to see when we're in the middle of a write.
  this.writing = false;

  // when true all writes will be buffered until .uncork() call
  this.corked = 0;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // a flag to know if we're processing previously buffered items, which
  // may call the _write() callback in the same tick, so that we don't
  // end up in an overlapped onwrite situation.
  this.bufferProcessing = false;

  // the callback that's passed to _write(chunk,cb)
  this.onwrite = function (er) {
    onwrite(stream, er);
  };

  // the callback that the user supplies to write(chunk,encoding,cb)
  this.writecb = null;

  // the amount that is being written when _write is called.
  this.writelen = 0;

  this.bufferedRequest = null;
  this.lastBufferedRequest = null;

  // number of pending user-supplied write callbacks
  // this must be 0 before 'finish' can be emitted
  this.pendingcb = 0;

  // emit prefinish if the only thing we're waiting for is _write cbs
  // This is relevant for synchronous Transform streams
  this.prefinished = false;

  // True if the error was already emitted and should not be thrown again
  this.errorEmitted = false;

  // count buffered requests
  this.bufferedRequestCount = 0;

  // allocate the first CorkedRequest, there is always
  // one allocated and free to use, and we maintain at most two
  this.corkedRequestsFree = new CorkedRequest(this);
}

WritableState.prototype.getBuffer = function writableStateGetBuffer() {
  var current = this.bufferedRequest;
  var out = [];
  while (current) {
    out.push(current);
    current = current.next;
  }
  return out;
};

(function () {
  try {
    Object.defineProperty(WritableState.prototype, 'buffer', {
      get: internalUtil.deprecate(function () {
        return this.getBuffer();
      }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.')
    });
  } catch (_) {}
})();

var Duplex;
function Writable(options) {
  Duplex = Duplex || require('./_stream_duplex');

  // Writable ctor is applied to Duplexes, though they're not
  // instanceof Writable, they're instanceof Readable.
  if (!(this instanceof Writable) && !(this instanceof Duplex)) return new Writable(options);

  this._writableState = new WritableState(options, this);

  // legacy.
  this.writable = true;

  if (options) {
    if (typeof options.write === 'function') this._write = options.write;

    if (typeof options.writev === 'function') this._writev = options.writev;
  }

  Stream.call(this);
}

// Otherwise people can pipe Writable streams, which is just wrong.
Writable.prototype.pipe = function () {
  this.emit('error', new Error('Cannot pipe, not readable'));
};

function writeAfterEnd(stream, cb) {
  var er = new Error('write after end');
  // TODO: defer error events consistently everywhere, not just the cb
  stream.emit('error', er);
  processNextTick(cb, er);
}

// If we get something that is not a buffer, string, null, or undefined,
// and we're not in objectMode, then that's an error.
// Otherwise stream chunks are all considered to be of length=1, and the
// watermarks determine how many objects to keep in the buffer, rather than
// how many bytes or characters.
function validChunk(stream, state, chunk, cb) {
  var valid = true;
  var er = false;
  // Always throw error if a null is written
  // if we are not in object mode then throw
  // if it is not a buffer, string, or undefined.
  if (chunk === null) {
    er = new TypeError('May not write null values to stream');
  } else if (!Buffer.isBuffer(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
    er = new TypeError('Invalid non-string/buffer chunk');
  }
  if (er) {
    stream.emit('error', er);
    processNextTick(cb, er);
    valid = false;
  }
  return valid;
}

Writable.prototype.write = function (chunk, encoding, cb) {
  var state = this._writableState;
  var ret = false;

  if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (Buffer.isBuffer(chunk)) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;

  if (typeof cb !== 'function') cb = nop;

  if (state.ended) writeAfterEnd(this, cb);else if (validChunk(this, state, chunk, cb)) {
    state.pendingcb++;
    ret = writeOrBuffer(this, state, chunk, encoding, cb);
  }

  return ret;
};

Writable.prototype.cork = function () {
  var state = this._writableState;

  state.corked++;
};

Writable.prototype.uncork = function () {
  var state = this._writableState;

  if (state.corked) {
    state.corked--;

    if (!state.writing && !state.corked && !state.finished && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
  }
};

Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
  // node::ParseEncoding() requires lower case.
  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new TypeError('Unknown encoding: ' + encoding);
  this._writableState.defaultEncoding = encoding;
  return this;
};

function decodeChunk(state, chunk, encoding) {
  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
    chunk = bufferShim.from(chunk, encoding);
  }
  return chunk;
}

// if we're already writing something, then just put this
// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, cb) {
  chunk = decodeChunk(state, chunk, encoding);

  if (Buffer.isBuffer(chunk)) encoding = 'buffer';
  var len = state.objectMode ? 1 : chunk.length;

  state.length += len;

  var ret = state.length < state.highWaterMark;
  // we must ensure that previous needDrain will not be reset to false.
  if (!ret) state.needDrain = true;

  if (state.writing || state.corked) {
    var last = state.lastBufferedRequest;
    state.lastBufferedRequest = new WriteReq(chunk, encoding, cb);
    if (last) {
      last.next = state.lastBufferedRequest;
    } else {
      state.bufferedRequest = state.lastBufferedRequest;
    }
    state.bufferedRequestCount += 1;
  } else {
    doWrite(stream, state, false, len, chunk, encoding, cb);
  }

  return ret;
}

function doWrite(stream, state, writev, len, chunk, encoding, cb) {
  state.writelen = len;
  state.writecb = cb;
  state.writing = true;
  state.sync = true;
  if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
  state.sync = false;
}

function onwriteError(stream, state, sync, er, cb) {
  --state.pendingcb;
  if (sync) processNextTick(cb, er);else cb(er);

  stream._writableState.errorEmitted = true;
  stream.emit('error', er);
}

function onwriteStateUpdate(state) {
  state.writing = false;
  state.writecb = null;
  state.length -= state.writelen;
  state.writelen = 0;
}

function onwrite(stream, er) {
  var state = stream._writableState;
  var sync = state.sync;
  var cb = state.writecb;

  onwriteStateUpdate(state);

  if (er) onwriteError(stream, state, sync, er, cb);else {
    // Check if we're actually ready to finish, but don't emit yet
    var finished = needFinish(state);

    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
      clearBuffer(stream, state);
    }

    if (sync) {
      /*<replacement>*/
      asyncWrite(afterWrite, stream, state, finished, cb);
      /*</replacement>*/
    } else {
        afterWrite(stream, state, finished, cb);
      }
  }
}

function afterWrite(stream, state, finished, cb) {
  if (!finished) onwriteDrain(stream, state);
  state.pendingcb--;
  cb();
  finishMaybe(stream, state);
}

// Must force callback to be called on nextTick, so that we don't
// emit 'drain' before the write() consumer gets the 'false' return
// value, and has a chance to attach a 'drain' listener.
function onwriteDrain(stream, state) {
  if (state.length === 0 && state.needDrain) {
    state.needDrain = false;
    stream.emit('drain');
  }
}

// if there's something in the buffer waiting, then process it
function clearBuffer(stream, state) {
  state.bufferProcessing = true;
  var entry = state.bufferedRequest;

  if (stream._writev && entry && entry.next) {
    // Fast case, write everything using _writev()
    var l = state.bufferedRequestCount;
    var buffer = new Array(l);
    var holder = state.corkedRequestsFree;
    holder.entry = entry;

    var count = 0;
    while (entry) {
      buffer[count] = entry;
      entry = entry.next;
      count += 1;
    }

    doWrite(stream, state, true, state.length, buffer, '', holder.finish);

    // doWrite is almost always async, defer these to save a bit of time
    // as the hot path ends with doWrite
    state.pendingcb++;
    state.lastBufferedRequest = null;
    if (holder.next) {
      state.corkedRequestsFree = holder.next;
      holder.next = null;
    } else {
      state.corkedRequestsFree = new CorkedRequest(state);
    }
  } else {
    // Slow case, write chunks one-by-one
    while (entry) {
      var chunk = entry.chunk;
      var encoding = entry.encoding;
      var cb = entry.callback;
      var len = state.objectMode ? 1 : chunk.length;

      doWrite(stream, state, false, len, chunk, encoding, cb);
      entry = entry.next;
      // if we didn't call the onwrite immediately, then
      // it means that we need to wait until it does.
      // also, that means that the chunk and cb are currently
      // being processed, so move the buffer counter past them.
      if (state.writing) {
        break;
      }
    }

    if (entry === null) state.lastBufferedRequest = null;
  }

  state.bufferedRequestCount = 0;
  state.bufferedRequest = entry;
  state.bufferProcessing = false;
}

Writable.prototype._write = function (chunk, encoding, cb) {
  cb(new Error('not implemented'));
};

Writable.prototype._writev = null;

Writable.prototype.end = function (chunk, encoding, cb) {
  var state = this._writableState;

  if (typeof chunk === 'function') {
    cb = chunk;
    chunk = null;
    encoding = null;
  } else if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding);

  // .end() fully uncorks
  if (state.corked) {
    state.corked = 1;
    this.uncork();
  }

  // ignore unnecessary end() calls.
  if (!state.ending && !state.finished) endWritable(this, state, cb);
};

function needFinish(state) {
  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
}

function prefinish(stream, state) {
  if (!state.prefinished) {
    state.prefinished = true;
    stream.emit('prefinish');
  }
}

function finishMaybe(stream, state) {
  var need = needFinish(state);
  if (need) {
    if (state.pendingcb === 0) {
      prefinish(stream, state);
      state.finished = true;
      stream.emit('finish');
    } else {
      prefinish(stream, state);
    }
  }
  return need;
}

function endWritable(stream, state, cb) {
  state.ending = true;
  finishMaybe(stream, state);
  if (cb) {
    if (state.finished) processNextTick(cb);else stream.once('finish', cb);
  }
  state.ended = true;
  stream.writable = false;
}

// It seems a linked list but it is not
// there will be only 2 of these for each stream
function CorkedRequest(state) {
  var _this = this;

  this.next = null;
  this.entry = null;

  this.finish = function (err) {
    var entry = _this.entry;
    _this.entry = null;
    while (entry) {
      var cb = entry.callback;
      state.pendingcb--;
      cb(err);
      entry = entry.next;
    }
    if (state.corkedRequestsFree) {
      state.corkedRequestsFree.next = _this;
    } else {
      state.corkedRequestsFree = _this;
    }
  };
}
}).call(this,require('_process'))
},{"./_stream_duplex":115,"_process":113,"buffer":105,"buffer-shims":104,"core-util-is":106,"events":107,"inherits":109,"process-nextick-args":112,"util-deprecate":127}],120:[function(require,module,exports){
'use strict';

var Buffer = require('buffer').Buffer;
/*<replacement>*/
var bufferShim = require('buffer-shims');
/*</replacement>*/

module.exports = BufferList;

function BufferList() {
  this.head = null;
  this.tail = null;
  this.length = 0;
}

BufferList.prototype.push = function (v) {
  var entry = { data: v, next: null };
  if (this.length > 0) this.tail.next = entry;else this.head = entry;
  this.tail = entry;
  ++this.length;
};

BufferList.prototype.unshift = function (v) {
  var entry = { data: v, next: this.head };
  if (this.length === 0) this.tail = entry;
  this.head = entry;
  ++this.length;
};

BufferList.prototype.shift = function () {
  if (this.length === 0) return;
  var ret = this.head.data;
  if (this.length === 1) this.head = this.tail = null;else this.head = this.head.next;
  --this.length;
  return ret;
};

BufferList.prototype.clear = function () {
  this.head = this.tail = null;
  this.length = 0;
};

BufferList.prototype.join = function (s) {
  if (this.length === 0) return '';
  var p = this.head;
  var ret = '' + p.data;
  while (p = p.next) {
    ret += s + p.data;
  }return ret;
};

BufferList.prototype.concat = function (n) {
  if (this.length === 0) return bufferShim.alloc(0);
  if (this.length === 1) return this.head.data;
  var ret = bufferShim.allocUnsafe(n >>> 0);
  var p = this.head;
  var i = 0;
  while (p) {
    p.data.copy(ret, i);
    i += p.data.length;
    p = p.next;
  }
  return ret;
};
},{"buffer":105,"buffer-shims":104}],121:[function(require,module,exports){
module.exports = require("./lib/_stream_passthrough.js")

},{"./lib/_stream_passthrough.js":116}],122:[function(require,module,exports){
(function (process){
var Stream = (function (){
  try {
    return require('st' + 'ream'); // hack to fix a circular dependency issue when used with browserify
  } catch(_){}
}());
exports = module.exports = require('./lib/_stream_readable.js');
exports.Stream = Stream || exports;
exports.Readable = exports;
exports.Writable = require('./lib/_stream_writable.js');
exports.Duplex = require('./lib/_stream_duplex.js');
exports.Transform = require('./lib/_stream_transform.js');
exports.PassThrough = require('./lib/_stream_passthrough.js');

if (!process.browser && process.env.READABLE_STREAM === 'disable' && Stream) {
  module.exports = Stream;
}

}).call(this,require('_process'))
},{"./lib/_stream_duplex.js":115,"./lib/_stream_passthrough.js":116,"./lib/_stream_readable.js":117,"./lib/_stream_transform.js":118,"./lib/_stream_writable.js":119,"_process":113}],123:[function(require,module,exports){
arguments[4][95][0].apply(exports,arguments)
},{"./lib/_stream_transform.js":118,"dup":95}],124:[function(require,module,exports){
module.exports = require("./lib/_stream_writable.js")

},{"./lib/_stream_writable.js":119}],125:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

module.exports = Stream;

var EE = require('events').EventEmitter;
var inherits = require('inherits');

inherits(Stream, EE);
Stream.Readable = require('readable-stream/readable.js');
Stream.Writable = require('readable-stream/writable.js');
Stream.Duplex = require('readable-stream/duplex.js');
Stream.Transform = require('readable-stream/transform.js');
Stream.PassThrough = require('readable-stream/passthrough.js');

// Backwards-compat with node 0.4.x
Stream.Stream = Stream;



// old-style streams.  Note that the pipe method (the only relevant
// part of this class) is overridden in the Readable class.

function Stream() {
  EE.call(this);
}

Stream.prototype.pipe = function(dest, options) {
  var source = this;

  function ondata(chunk) {
    if (dest.writable) {
      if (false === dest.write(chunk) && source.pause) {
        source.pause();
      }
    }
  }

  source.on('data', ondata);

  function ondrain() {
    if (source.readable && source.resume) {
      source.resume();
    }
  }

  dest.on('drain', ondrain);

  // If the 'end' option is not supplied, dest.end() will be called when
  // source gets the 'end' or 'close' events.  Only dest.end() once.
  if (!dest._isStdio && (!options || options.end !== false)) {
    source.on('end', onend);
    source.on('close', onclose);
  }

  var didOnEnd = false;
  function onend() {
    if (didOnEnd) return;
    didOnEnd = true;

    dest.end();
  }


  function onclose() {
    if (didOnEnd) return;
    didOnEnd = true;

    if (typeof dest.destroy === 'function') dest.destroy();
  }

  // don't leave dangling pipes when there are errors.
  function onerror(er) {
    cleanup();
    if (EE.listenerCount(this, 'error') === 0) {
      throw er; // Unhandled stream error in pipe.
    }
  }

  source.on('error', onerror);
  dest.on('error', onerror);

  // remove all the event listeners that were added.
  function cleanup() {
    source.removeListener('data', ondata);
    dest.removeListener('drain', ondrain);

    source.removeListener('end', onend);
    source.removeListener('close', onclose);

    source.removeListener('error', onerror);
    dest.removeListener('error', onerror);

    source.removeListener('end', cleanup);
    source.removeListener('close', cleanup);

    dest.removeListener('close', cleanup);
  }

  source.on('end', cleanup);
  source.on('close', cleanup);

  dest.on('close', cleanup);

  dest.emit('pipe', source);

  // Allow for unix-like usage: A.pipe(B).pipe(C)
  return dest;
};

},{"events":107,"inherits":109,"readable-stream/duplex.js":114,"readable-stream/passthrough.js":121,"readable-stream/readable.js":122,"readable-stream/transform.js":123,"readable-stream/writable.js":124}],126:[function(require,module,exports){
arguments[4][80][0].apply(exports,arguments)
},{"buffer":105,"dup":80}],127:[function(require,module,exports){
arguments[4][99][0].apply(exports,arguments)
},{"dup":99}],128:[function(require,module,exports){
module.exports = function isBuffer(arg) {
  return arg && typeof arg === 'object'
    && typeof arg.copy === 'function'
    && typeof arg.fill === 'function'
    && typeof arg.readUInt8 === 'function';
}
},{}],129:[function(require,module,exports){
(function (process,global){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

var formatRegExp = /%[sdj%]/g;
exports.format = function(f) {
  if (!isString(f)) {
    var objects = [];
    for (var i = 0; i < arguments.length; i++) {
      objects.push(inspect(arguments[i]));
    }
    return objects.join(' ');
  }

  var i = 1;
  var args = arguments;
  var len = args.length;
  var str = String(f).replace(formatRegExp, function(x) {
    if (x === '%%') return '%';
    if (i >= len) return x;
    switch (x) {
      case '%s': return String(args[i++]);
      case '%d': return Number(args[i++]);
      case '%j':
        try {
          return JSON.stringify(args[i++]);
        } catch (_) {
          return '[Circular]';
        }
      default:
        return x;
    }
  });
  for (var x = args[i]; i < len; x = args[++i]) {
    if (isNull(x) || !isObject(x)) {
      str += ' ' + x;
    } else {
      str += ' ' + inspect(x);
    }
  }
  return str;
};


// Mark that a method should not be used.
// Returns a modified function which warns once by default.
// If --no-deprecation is set, then it is a no-op.
exports.deprecate = function(fn, msg) {
  // Allow for deprecating things in the process of starting up.
  if (isUndefined(global.process)) {
    return function() {
      return exports.deprecate(fn, msg).apply(this, arguments);
    };
  }

  if (process.noDeprecation === true) {
    return fn;
  }

  var warned = false;
  function deprecated() {
    if (!warned) {
      if (process.throwDeprecation) {
        throw new Error(msg);
      } else if (process.traceDeprecation) {
        console.trace(msg);
      } else {
        console.error(msg);
      }
      warned = true;
    }
    return fn.apply(this, arguments);
  }

  return deprecated;
};


var debugs = {};
var debugEnviron;
exports.debuglog = function(set) {
  if (isUndefined(debugEnviron))
    debugEnviron = process.env.NODE_DEBUG || '';
  set = set.toUpperCase();
  if (!debugs[set]) {
    if (new RegExp('\\b' + set + '\\b', 'i').test(debugEnviron)) {
      var pid = process.pid;
      debugs[set] = function() {
        var msg = exports.format.apply(exports, arguments);
        console.error('%s %d: %s', set, pid, msg);
      };
    } else {
      debugs[set] = function() {};
    }
  }
  return debugs[set];
};


/**
 * Echos the value of a value. Trys to print the value out
 * in the best way possible given the different types.
 *
 * @param {Object} obj The object to print out.
 * @param {Object} opts Optional options object that alters the output.
 */
/* legacy: obj, showHidden, depth, colors*/
function inspect(obj, opts) {
  // default options
  var ctx = {
    seen: [],
    stylize: stylizeNoColor
  };
  // legacy...
  if (arguments.length >= 3) ctx.depth = arguments[2];
  if (arguments.length >= 4) ctx.colors = arguments[3];
  if (isBoolean(opts)) {
    // legacy...
    ctx.showHidden = opts;
  } else if (opts) {
    // got an "options" object
    exports._extend(ctx, opts);
  }
  // set default options
  if (isUndefined(ctx.showHidden)) ctx.showHidden = false;
  if (isUndefined(ctx.depth)) ctx.depth = 2;
  if (isUndefined(ctx.colors)) ctx.colors = false;
  if (isUndefined(ctx.customInspect)) ctx.customInspect = true;
  if (ctx.colors) ctx.stylize = stylizeWithColor;
  return formatValue(ctx, obj, ctx.depth);
}
exports.inspect = inspect;


// http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
inspect.colors = {
  'bold' : [1, 22],
  'italic' : [3, 23],
  'underline' : [4, 24],
  'inverse' : [7, 27],
  'white' : [37, 39],
  'grey' : [90, 39],
  'black' : [30, 39],
  'blue' : [34, 39],
  'cyan' : [36, 39],
  'green' : [32, 39],
  'magenta' : [35, 39],
  'red' : [31, 39],
  'yellow' : [33, 39]
};

// Don't use 'blue' not visible on cmd.exe
inspect.styles = {
  'special': 'cyan',
  'number': 'yellow',
  'boolean': 'yellow',
  'undefined': 'grey',
  'null': 'bold',
  'string': 'green',
  'date': 'magenta',
  // "name": intentionally not styling
  'regexp': 'red'
};


function stylizeWithColor(str, styleType) {
  var style = inspect.styles[styleType];

  if (style) {
    return '\u001b[' + inspect.colors[style][0] + 'm' + str +
           '\u001b[' + inspect.colors[style][1] + 'm';
  } else {
    return str;
  }
}


function stylizeNoColor(str, styleType) {
  return str;
}


function arrayToHash(array) {
  var hash = {};

  array.forEach(function(val, idx) {
    hash[val] = true;
  });

  return hash;
}


function formatValue(ctx, value, recurseTimes) {
  // Provide a hook for user-specified inspect functions.
  // Check that value is an object with an inspect function on it
  if (ctx.customInspect &&
      value &&
      isFunction(value.inspect) &&
      // Filter out the util module, it's inspect function is special
      value.inspect !== exports.inspect &&
      // Also filter out any prototype objects using the circular check.
      !(value.constructor && value.constructor.prototype === value)) {
    var ret = value.inspect(recurseTimes, ctx);
    if (!isString(ret)) {
      ret = formatValue(ctx, ret, recurseTimes);
    }
    return ret;
  }

  // Primitive types cannot have properties
  var primitive = formatPrimitive(ctx, value);
  if (primitive) {
    return primitive;
  }

  // Look up the keys of the object.
  var keys = Object.keys(value);
  var visibleKeys = arrayToHash(keys);

  if (ctx.showHidden) {
    keys = Object.getOwnPropertyNames(value);
  }

  // IE doesn't make error fields non-enumerable
  // http://msdn.microsoft.com/en-us/library/ie/dww52sbt(v=vs.94).aspx
  if (isError(value)
      && (keys.indexOf('message') >= 0 || keys.indexOf('description') >= 0)) {
    return formatError(value);
  }

  // Some type of object without properties can be shortcutted.
  if (keys.length === 0) {
    if (isFunction(value)) {
      var name = value.name ? ': ' + value.name : '';
      return ctx.stylize('[Function' + name + ']', 'special');
    }
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    }
    if (isDate(value)) {
      return ctx.stylize(Date.prototype.toString.call(value), 'date');
    }
    if (isError(value)) {
      return formatError(value);
    }
  }

  var base = '', array = false, braces = ['{', '}'];

  // Make Array say that they are Array
  if (isArray(value)) {
    array = true;
    braces = ['[', ']'];
  }

  // Make functions say that they are functions
  if (isFunction(value)) {
    var n = value.name ? ': ' + value.name : '';
    base = ' [Function' + n + ']';
  }

  // Make RegExps say that they are RegExps
  if (isRegExp(value)) {
    base = ' ' + RegExp.prototype.toString.call(value);
  }

  // Make dates with properties first say the date
  if (isDate(value)) {
    base = ' ' + Date.prototype.toUTCString.call(value);
  }

  // Make error with message first say the error
  if (isError(value)) {
    base = ' ' + formatError(value);
  }

  if (keys.length === 0 && (!array || value.length == 0)) {
    return braces[0] + base + braces[1];
  }

  if (recurseTimes < 0) {
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    } else {
      return ctx.stylize('[Object]', 'special');
    }
  }

  ctx.seen.push(value);

  var output;
  if (array) {
    output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
  } else {
    output = keys.map(function(key) {
      return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
    });
  }

  ctx.seen.pop();

  return reduceToSingleString(output, base, braces);
}


function formatPrimitive(ctx, value) {
  if (isUndefined(value))
    return ctx.stylize('undefined', 'undefined');
  if (isString(value)) {
    var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
                                             .replace(/'/g, "\\'")
                                             .replace(/\\"/g, '"') + '\'';
    return ctx.stylize(simple, 'string');
  }
  if (isNumber(value))
    return ctx.stylize('' + value, 'number');
  if (isBoolean(value))
    return ctx.stylize('' + value, 'boolean');
  // For some reason typeof null is "object", so special case here.
  if (isNull(value))
    return ctx.stylize('null', 'null');
}


function formatError(value) {
  return '[' + Error.prototype.toString.call(value) + ']';
}


function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  for (var i = 0, l = value.length; i < l; ++i) {
    if (hasOwnProperty(value, String(i))) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          String(i), true));
    } else {
      output.push('');
    }
  }
  keys.forEach(function(key) {
    if (!key.match(/^\d+$/)) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          key, true));
    }
  });
  return output;
}


function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
  var name, str, desc;
  desc = Object.getOwnPropertyDescriptor(value, key) || { value: value[key] };
  if (desc.get) {
    if (desc.set) {
      str = ctx.stylize('[Getter/Setter]', 'special');
    } else {
      str = ctx.stylize('[Getter]', 'special');
    }
  } else {
    if (desc.set) {
      str = ctx.stylize('[Setter]', 'special');
    }
  }
  if (!hasOwnProperty(visibleKeys, key)) {
    name = '[' + key + ']';
  }
  if (!str) {
    if (ctx.seen.indexOf(desc.value) < 0) {
      if (isNull(recurseTimes)) {
        str = formatValue(ctx, desc.value, null);
      } else {
        str = formatValue(ctx, desc.value, recurseTimes - 1);
      }
      if (str.indexOf('\n') > -1) {
        if (array) {
          str = str.split('\n').map(function(line) {
            return '  ' + line;
          }).join('\n').substr(2);
        } else {
          str = '\n' + str.split('\n').map(function(line) {
            return '   ' + line;
          }).join('\n');
        }
      }
    } else {
      str = ctx.stylize('[Circular]', 'special');
    }
  }
  if (isUndefined(name)) {
    if (array && key.match(/^\d+$/)) {
      return str;
    }
    name = JSON.stringify('' + key);
    if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
      name = name.substr(1, name.length - 2);
      name = ctx.stylize(name, 'name');
    } else {
      name = name.replace(/'/g, "\\'")
                 .replace(/\\"/g, '"')
                 .replace(/(^"|"$)/g, "'");
      name = ctx.stylize(name, 'string');
    }
  }

  return name + ': ' + str;
}


function reduceToSingleString(output, base, braces) {
  var numLinesEst = 0;
  var length = output.reduce(function(prev, cur) {
    numLinesEst++;
    if (cur.indexOf('\n') >= 0) numLinesEst++;
    return prev + cur.replace(/\u001b\[\d\d?m/g, '').length + 1;
  }, 0);

  if (length > 60) {
    return braces[0] +
           (base === '' ? '' : base + '\n ') +
           ' ' +
           output.join(',\n  ') +
           ' ' +
           braces[1];
  }

  return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
}


// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.
function isArray(ar) {
  return Array.isArray(ar);
}
exports.isArray = isArray;

function isBoolean(arg) {
  return typeof arg === 'boolean';
}
exports.isBoolean = isBoolean;

function isNull(arg) {
  return arg === null;
}
exports.isNull = isNull;

function isNullOrUndefined(arg) {
  return arg == null;
}
exports.isNullOrUndefined = isNullOrUndefined;

function isNumber(arg) {
  return typeof arg === 'number';
}
exports.isNumber = isNumber;

function isString(arg) {
  return typeof arg === 'string';
}
exports.isString = isString;

function isSymbol(arg) {
  return typeof arg === 'symbol';
}
exports.isSymbol = isSymbol;

function isUndefined(arg) {
  return arg === void 0;
}
exports.isUndefined = isUndefined;

function isRegExp(re) {
  return isObject(re) && objectToString(re) === '[object RegExp]';
}
exports.isRegExp = isRegExp;

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}
exports.isObject = isObject;

function isDate(d) {
  return isObject(d) && objectToString(d) === '[object Date]';
}
exports.isDate = isDate;

function isError(e) {
  return isObject(e) &&
      (objectToString(e) === '[object Error]' || e instanceof Error);
}
exports.isError = isError;

function isFunction(arg) {
  return typeof arg === 'function';
}
exports.isFunction = isFunction;

function isPrimitive(arg) {
  return arg === null ||
         typeof arg === 'boolean' ||
         typeof arg === 'number' ||
         typeof arg === 'string' ||
         typeof arg === 'symbol' ||  // ES6 symbol
         typeof arg === 'undefined';
}
exports.isPrimitive = isPrimitive;

exports.isBuffer = require('./support/isBuffer');

function objectToString(o) {
  return Object.prototype.toString.call(o);
}


function pad(n) {
  return n < 10 ? '0' + n.toString(10) : n.toString(10);
}


var months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep',
              'Oct', 'Nov', 'Dec'];

// 26 Feb 16:19:34
function timestamp() {
  var d = new Date();
  var time = [pad(d.getHours()),
              pad(d.getMinutes()),
              pad(d.getSeconds())].join(':');
  return [d.getDate(), months[d.getMonth()], time].join(' ');
}


// log is just a thin wrapper to console.log that prepends a timestamp
exports.log = function() {
  console.log('%s - %s', timestamp(), exports.format.apply(exports, arguments));
};


/**
 * Inherit the prototype methods from one constructor into another.
 *
 * The Function.prototype.inherits from lang.js rewritten as a standalone
 * function (not on Function.prototype). NOTE: If this file is to be loaded
 * during bootstrapping this function needs to be rewritten using some native
 * functions as prototype setup using normal JavaScript does not work as
 * expected during bootstrapping (see mirror.js in r114903).
 *
 * @param {function} ctor Constructor function which needs to inherit the
 *     prototype.
 * @param {function} superCtor Constructor function to inherit prototype from.
 */
exports.inherits = require('inherits');

exports._extend = function(origin, add) {
  // Don't do anything if add isn't an object
  if (!add || !isObject(add)) return origin;

  var keys = Object.keys(add);
  var i = keys.length;
  while (i--) {
    origin[keys[i]] = add[keys[i]];
  }
  return origin;
};

function hasOwnProperty(obj, prop) {
  return Object.prototype.hasOwnProperty.call(obj, prop);
}

}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"./support/isBuffer":128,"_process":113,"inherits":109}]},{},[1]);
